VIETNAM ACADEMY OF
SCIENCE AND TECHNOLOGY
MINISTRY OF EDUCATION
INSTITUTE OF GEOGRAPHY
DO THI VAN HUONG
STUDY, ASSESSEMENT OF BIOCLIMATIC RESOURCES IN THE
NORTHEAST REGION OF VIETNAM FOR DEVELOPMENT OF A
FEW AGRICULTURAL CROPS AND FOREST TREES THAT HAVE
Chuyên ngành: Speciality: Geographical and environmental resources
62 44 02 19
SUMMARY OF Ph.D DISSERTATION IN GEOGRAPHY
Ha Noi – 2014
Dissertation has been completed at:
Institute of geography, Viet Nam academy of science and technology
1. Associate professor Dr. Nguyen Khanh Van
2. Dr Do Huu Thu
Reviwer 1: Associate professor Dr. Tran Van Con
Reviwer 2: Professor Dr. Tran Thuc
Reviwer 3: Associate professor Dr. Nguyen Thi Hong
The dissertation is defended in front of board of examination of dissertation at
institute level held at the institute of geography in 18 Hoang Quoc Viet, Cau
Giay, Ha Noi
at……… on……… 2014
The dissertation can be found in:
- National library
- Library of institute of geography, Viet Nam academy of science and
1. Reasons for choosing project
Climate is the first natural factor, the condition of all regular
development process, natural metabolism. Study on assessement of
bioclimatic conditions of vegetation covers provides essential information
needed about characteristics of bioclimate as a basis for serving
orientation of development planning of agriculture and forestry to help
managers make the structure of agricultural crops and forest trees
reasonable to fully utilize the strengths of each territory in order to
achieve high efficiency and sustainability..
Northeast region of Vietnam is one of the mountainous and
midland areas of our country, the natural geographical region has an
important significance both in terms of nature, economy and politics.
During the past several years, the area has always been regarded as a rich
potential for developing agro- forestry and areas specializing in the
growing of special crops with high economic value. Agricultural and
Forestry economimy always account for high proportion of the economic
structure of Northeast region, especially playing an important role in the
economic development of the region . However, currently Northeast
region is still underdeveloped, agricultural and forestry production in the
region has not developed commensurating with the level that it may be ,
people's life faces a lot of difficulties. Identifying areas that are able to
expand agricultural and forestry production, afforestation, promote
protection and development of forest resources and selection of tree
group for development in accordance with the climatic conditions of the
region is the critical issues. Assessment of bioclimatic conditions in a
scientific way for the development of sustainable agriculture and forestry
are necessary, having high practical significance.
We believe that selection of study and asessement of bioclimatic
resources for the development of agricultural crops, forestry trees ,
perennial crops, medicinal plants with economic value is very necessary.
Individually, as a graduate student with the practical needs and the desire
to contribute to sustainable development of socio-economics of Northeast
region of Viet Nam, the author has chosen the project: "Study on
-2assessement of bioclimatic resources in Northeast region of Vietnam for
development of agricultural crops and forest trees with economic value
"to perform PhD dissertation in geography.
2. Objectives and study tasks
- Study on characteristics of bioclimatic resouces in Northeast
region to elucidate the potential of bioclimate to establish the scientific
basis for exploitation of bioclimatic resources
development of agricultural and forestry production.
- Recommendation of rational using bioclimatic units for
sustainable development of agricultural crops and forestry trees in
- Overview of documents of bioclimate, studies on bioclimate
assessment and other documents related to the place of study, designing
rationale for the use of the project.
- Analyzing factors that shape the climate, mapping of bioclimatenatural vegetation covers in Northeast region on scale of 1: 500.000;
Analysis of bioclimatic characteristics to clarify rules of differentiation of
bioclimatic resources, distribution law, the structure of external appearance,
ecological processes and vegetation cover types on studied territor.
- Assessment of bioclimatic resources for the development of a
number of agricultural crops and forest trees; assessment of appropriate
levels of bioclimatic types for acacia hybrid (assessment for total
Northeast region at map on scale 1: 500,000), tea plant (Thai Nguyen
Province on scale 1: 100,000), star anise (in Lang son province on scale
of 1: 100,000), black cardamom (Sa Pa district, Lao Cai province on scale
of 1: 50,000) and recommendation of orientations of rational exploitation
and use of bioclimatic resources and sustainable development of
agricultural crops and forest trees.
3. Limited scope of study
- Limited scope of territory :Studied territory is limited within
Northeast region with natural area of 64 952 km ² (accounting for 20% of
total area of the country), including 11 provinces. Geographical studied
places focused on mainland, not included part of the sea and islands.
- Limited scientific scope: The dissertation only focuses on
characteristics, differentiation of bioclimatic conditions and assessment
of bioclimatic adaptation for developing a number of agricultural crops
and forest trees with economic value in Northeast region ( Acacia hybrid
-3tree, midland tea plant, star anise and black cardamom);orientation of
spatial rational use of bioclimatic resources in agricultural and forestry
production in Northeast region.
4. Scentific signìficance of the dissertation
- The dissertation has elucidated nature of characteristics and
differentiation of bioclimatic resources on the territory from which
recommends orientation of rational exploitation and use of territorial
bioclimatic resources for sustainable socioeconomic development
- Practical signìficance of the dissertation: In order to orientate
sustainable development of agricultural and forestry production, the
results of the dissertation will be the scientific basis for reasonable
maintenance, restoration, protection and development of vegetation
covers in natural forest and planted forest, contributing to
recommendation of structure of agricultural crops and forest trees, areas
spicializing in growing industrial trees, medicinal plants that have high
economic value in accordance with specific characteristics of bioclimatic
resources on territory of northeast region of Vietnam. :
5. New contribution of the dissertation
Indicator System and bioclimatic- vegetation maps of Northeast
region on scale of 1:500.000 has reflected bioclimatic characteritics and
differentiation characteristics of vegetation covers in Northeast region.
Bioclimatic units carry specific characteristics of the studied area..
Assessement of bioclimatic resources and other natural factors for
development of agricultural crops and forest trees with economic value is the
scientific basis for the rational spartial arrangement of production, contributing
to the sustainable development of agricultural and forestry sectors in Northeast
6. Theoretical points for defending
- Theoretical point 1: Midland and mountainous area in North East
region have diverse natural conditions and bioclimatic natural resouces
reflecting diverse aspect, abundant bioclimatic resources and climatic
differentation according to its own rules. Bioclimatic classification. It reflects
the structure of vegetation mulch -vegetation types of the studied area.
- Theoretical point 2: Applying the method of assessing ecological
adaptation, assessing the appropriate level of bioclimatic conditions for a
few agricultural crops and forest trees, medicinal plants that have high
economic value, the dissertation has developed a scientific basis
necessary for proper orientation of using bioclimatic resources, spartial
arrangement of areas pf producing forest trees and areas specializing in
-4the growing industrial plants, medicinal plants on the territory of
northeast region of Vietnam.
7. Sources of Document
- The results of the study, field survey following routes.
- Climatic data of 34 meteorological stations and rain gauge
stations of Northeast region
- In addition to the documents that have already been published having
content related to the dissertation, the graduate student herself collected
materials and data from the NAFOSTED project (2012-2014 by Assoc. Dr.
Nguyen Khanh Van and the graduate student is a member directly taking part
in this project.
- Falcilities of maps of special subjects serving for mapping in the
dissertation include: Topographic map of Northeast region on scale of
1:500.000; Soil Map of Thai Nguyen, Lang Son on scale of 1:100.000, soil
map Sa Pa District, Lao Cai Province on scale of 1:50.000 ; The projects,
scientific reports on investigations of natural and socio-economic conditions, ,
climatic resources in Northeast region.
8. Structure of the disertation
The disertation is presented in writing consisting of 150 typed
pages in A 4 size, 34 tables, 30 figures, lists of 122 references in
Vietnamese and foreign languages. Besides the introduction, conclusion
and references, the dissertation has three chapters including:
Chapter 1: The theoretical basis for the study and assessement of
bioclimatic resources for development of agricultural and forestry
Chapter 2: Characteristics of climate and bioclimatic resources in
Chapter 3: Assessment of bioclimatic resources in Northeast
region for development of some agricultural crops and forest trees.
Chapter 1:THEORETICAL BASIS FOR STUDY AND
ASSESSEMENT OF BIOCLIMATIC RESOURCES
FOR DEVELOPMENT AGRICULTURAL AND FORESTRY
1.1. Some basic terms
Climate applications is a science that studies climate in relation to a
specific object; analysing, elucidating the positive and negative impact of
climate on the object to provide the right, reasonable solutions to take
advantage and enhance the positive impacts, prevent negative impacts of
climate. The basic direction of study on climate applications such as
-5agriculture climate, forestry climate, medicine climate, tourism climate,
construction climate, transportation climate, Military climate.
Bioclimatology is a subject to study association between climatology and
ecology, the effects of climate to living organism. Bioclimatology focuses
on study on impact of climatic factors (radiation, temperature, humidity
.ect..) for a long time and tracks the impact of weather each day, each month,
studying climate within the region and in each small area (micro-climate), in
landscape and barn equipment created by humans for plants and animals.
Study on bioclimate is the basis for study of living organism’s adaptation to
enhance the productivity in a given environment ".
Study on some of the main directions of bioclimate (agrobioclimate, natural vegetation bioclimate, human bioclimate) continues to
be interested in, promoting both scientific and practical aspects.
1.2. Historical Overview of bioclimate -natural vegetation covers
Study of bioclimate-natural vegetation cover has been one of the
directions of studies for a long time. Many research works of scientists in the
country and foreign countries has high scientific and practical significance.
In fact, study results of bioclimate has provided a scientific basis for
geographic vegetation in determining the distribution of plant species, as well
as the ecological characteristics of generating natural vegetation covers. The
climate and vegetation have very close relationships. Natural vegetation is
regarded as indicators of climatic conditions corresponding to a climatic
type, havings a certain primary vegetation type.
1.2.1. Overview of research works on the world
The process of forming a direction of climatic classification on the
basis of plant ecology is a long process and are always developed with
different scientific advances by plant taxonomists , climatologists
supplemented by study results of landscapists.
In recent years, study direction of applications of bioclimate-natural
Vegetation covers relationship has been promoted having practical
significance, especially in the context of climate change..
Currently, scientists in the world are continuing to study and develop
this direction of study Application scope of studying bioclimate-natural
vegetation does not limit to the study for the purpose of assessing
adaptation of crop ecology, but studying forest fire warning, protection of
natural forest resources and vegetation covers for purposes of studying
adaptation and coping with climate change is also actively promoted
1.2.2. Over view of studies in Vietnam
Study of bioclimate in vegetation cover classification and
agriculture and forestry in general has been summarized in Thai Van
-6Trung ‘s works "forest vegetation cover of Vietnam." In the next studies
of Schmid (1962), Duong Huu Thoi, Pham Hoang Ho (1960) .
bioclimatic factors were applied to the description, explanation of the
formation, differentiation of the types of Vegetation Covers in different
regions of our country.
A number of subsequent studies, investigations and assessement of
climatic resources performed by Lee (1973), Vu Tu Lap (1976), Nguyen
Duc Ngu, Nguyen Trong Hieu (1985) Lam Cong Dinh (1992), Nguyen
Viet Pho, Vu Van Tuan (1993), Nguyen Duc Ngu, Nguyen Trong Hieu
(2004) analyzed the characteristics of climate and resources in Vietnam.
In addition, sudies on assessement of climatic resources of Vietnam are
also mentioned in some coursebooks of Vietnam natural geography,
ecologcal economy , bioclimatic basis written by the authors: Nguyen
Duc Chinh, Vu Tu Lap , Le Ba Thao, Nguyen Phap, Nguyen Khanh Van
* Northeast region
The study of climate in the specific areas, locallities of Northeast
region has been integrated in the findings of climate studies in Vietnam,
or in specific localities of Northeast region through the results of the
studies from the Hydrometeorological stations. However,there are little
separate works of study on assessement of bioclimatic resources
assessment for development of agricultural crops and forest trees of the
region. Realizing that this is the direction of studying climate
applications having high practical significance, the author would like to
be allowed to inherit and continue developing the previous studies.
1.3. Overview of studies on agricultural crops, forest trees
Currently, many studies of forest trees, industrial trees and
medicinal plants have been invested and put into practical applications.
Some of the main forest trees in our country as Acacia, Pine tree, gum
tree (Eucalyptus), Manglietia conifera ... have been studied in many
works carried out by authors such as Vu Tien Hinh; Dao Cong Khanh;Vu
Nham, Nguyen Ngoc Lung, ... These study results have made important
contribution to the process of restoring vegetation covers, development
of planted forest in Vietnam.
Studies of evaluating and classifying the levels of ecological
adaptability of plant groups (especially industrial trees, medicinal plants),
specific crops. Many scientists in the agriculture, biology, geography and
medicinal plants are interested in these studies and have obtained specific
results. The dissertation has listed some studies of agricultural crops,
assessment of the level of adaptation to the climatic conditions of
industrial trees , medicinal plants performed by Le Trong Cuc Nguyen
-7Dai Khanh, Pham Chi Thanh, Do Tat Loi.
Analysis of the results of the projects helps the author get more
scientific data for studying, analysis, assessement of bioclimatic
resources for the development of some valuable Agricultural crops and
forest trees in Northeast region of Vietnam.
1.4. Several classification systems, division of bioclimateVegetation cover types in Vietnam.
In the study of climate, there have been a number of documents
mentioning, analysing, classifying and distributing bioclimate-natural
vegetation covers. Typically, there are studies performed by Vu Tu Lap,
Thai Van Trung, Lam Cong Dinh, author groups of the Institute of
Inheriting the results, classification, distribution of bioclimatic types
obtained by various authors in the country, analyzing the advantages and
disadvantages of these methods of bioclimate classfication so that the
author can select most appropriate classification method of bioclimatenatural vegetation covers on the territory. In the process of study,
classification, bioclimatic mapping in Northeast region, the author applied
the classification method by the authors of Institute of Geography,
selecting criteria for classifying levels of bioclimatic types in map of
bioclimate-natural vegetation covers in Northeast region of Viet Nam…
1.5. General theory of climatic resources assessment for the
development of agricultural and forestry production
* Objects and assessement unit
Objects assessed are the bioclimatic units, bioclimate-resources
units, specific crops: Acacia hybrid tree, Midland tea plant star anise,
black cardamom. assessement units used when bioclimate is assessed for
development of agricultural crops and forest trees in Northeast region (in
bioclimatic map on scale of 1: 500,000) are units.of bioclimatic type.
Assessment unit of bioclimate for a specific crop (in bioclimatic map on
scale of 1: 100.000, 1: 50.000) is bioclimate-soil.
Contents of assessement: The contens consist of determining
characteristics of climatic resources on the territory, assessement of
bioclimatic types for development of specific agricultural crops and forest
trees to recommend orientation of rational and efficient use of
*The dissertation designs various steps of assessement for forest
trees (acacia hybrid), industrial trees (tea, star anise), medicinal plant (black
Assessement of bioclimatic adaptation was performed through the
following steps: Selecting and designing assessment indicator system;
-8scale, arithmetic mean; identifing methods of assessment and applying
studied territory. Asessement of bioclimatic resources,
bioclimate-esources for the purpose of crop development.
The disertation applied the method of calculating componential
scores by using the fomular. of calculating arithmetic mean
Xa = (1/∑ ki) ∑ kiXi
In which: Xa: scores for general assessement of total area a; ki:
weight of i factor; Xi: score for i factor; n: number of assessed factors
The assessment results will find out the most appropriate unit of
bioclimate-resources for development of agricultural crops and forest
trees in Northeast region.
* Classification of asessement results and recommendations of
their use After the results were obtained, applications to practice must
be verified and classified for each bioclimatic unit, bioclimate-resource.
That is a combination of bioclimatic group units, with the same
appropriate level for crops that were assessed having the same type of
resource potential or the same conditions for crop development.
1.6. Points of view and methods of study
* The dissertation used points of view such as: systematic point of
view, territorial point of view, historical point of view and view of
sustainable development. In particular, the views and synthesis system
were the key point.
* Methodology of study:The dissertation used methods of study as
follows: Method of collecting, analyzing and processing data; field
survey methods, interviewing experts; method of statistical analysis;
Method of typing, climatic classification; Assessment methods of plants
that adapt to ecology; Methods of mapping and geographic information
* Procedures of study: After conducting field surveys, collecting data
and processing related documents, the author conducted the study following
different steps: Step 1: Gathering documents and data, analysis and assesement
of natural and socioeconomic conditions of Northeast region; Step 2:
Analyzing characteristics of bioclimatic resources, bioclimatic mapping
Northeast region; Step 3: Assessing bioclimatic resources in Northeast region
for developing some agricultural crops and forest trees that have economic
value in this region.
-9Subconclusion of chapter 1
1 . The results of the study performed by many authors in the country
and foreign countries shows that bioclimate , bioclimate- natural vegetation
cover is a direction of study that has a long history , contributed ,enriched ,
enlightened by the results of many branches of sciences of earth sciences in
general. This is a real direction of study having both theorical and practical
significance. Currently study of bioclimate is continuing to be studied by
many scientists to promote the application to solve practical problems .
The findings of agricultural crops and forest trees are regarded as an important
document for the author to inherit and promote further study in order to obtain
results in the the dissertation.
2. Northeast region has natural area of 63 952 km ² (accounting for
about 20% of the country). This is a vast natural geographical area
having special bioclimatic resources and diverse complex climatic
differentiation.. There are many scientific studies of climate that mention
climate in Northeast region but they only limit to the level of general
study, not studying the entire contents of northeast region of Vietnam. In
contrast, there are a number of projects for a department or a province
located in Northeast region. There haven’t been any works analyzing
bioclimatic resources in the region specifically and in detail(at the rate of
study / 1500.000). Therefore, the study of the dissertation on bioclimatic
resources on Northeast territory has sufficient scientific basis to be
performed. The results of the analysis in chapter 1, the points of view and
methods of study are a theoretical basis for the author to review, select
and apply appropriately to study on assessement of bioclimatic resources
in order to develop some kind of Agricultural crops and forest trees
having economic value, contributing to hunger eradication and Poverty
reduction, optimal use of natural resources of Northeast region.
CHAPTER 2: CLIMATE AND BIOCLIMATC RESOURCES IN THE
NORTH EAST AREA OF VIETNAM
2.1. Factors forming and affecting bioclimatic resources
2.1.1. Natural factors forming climate of North east region of Viet Nam
Factors forming climate of the northeast region include three factors:
solar radiation, circulation of atmosphere and factorgroup of buffer surface .
* Northeast region (20º40’B -23°22’B, 103°31’-108°31’D )covers the
whole notheast area with its natural area of 63.952 km² (accounting for 20%
area of the whole country), which consists of 11 provinces (Quang Ninh, Lang
Son, Cao Bang, Bac Can, Thai Nguyen, Yen Bai, Lao Cai, Ha Giang, Tuyen
Quang, Phu Tho, Bac Giang) (map1.1) . With the location and territories
-10mentioned above, the area plays an extremely important role in eclology,
environment, society, economy, security and national defence.
The geographical location has detemined that the north east region
has radiation regime with tropic style. Generally, the area is abundant in
radiation with more than 200 kcal/cm² per year, Such amount of radiation
ensures the existance of tropical rain forest vegetation covers and rain
appears in many places of the region in rainy season
* North east region is influenced by circulation regime of internal
tropical monsoon , , . In the spere of the region in sumer the
prevailing winds blow in the region from the sea ( northeast trade winds
that dominates the north hemisphere) have south and southwest direction.
In winter the prevailing winds blow from continent northwardly and
norhthesterly. Shift of wind regimes causes contrast between heat regimes
and between annual precipitation in the place of study .
* Factor group of buffer surface include 2 factors: factor group of
geology and terrain and factorgroup of hydrography, soils and vegetation
- Factor group of geology and terrain: Differentiation of terrain by
east west com bination and north south combination plus specific
characteristic of the area (mountain, hill and plain) has caused the climate
in the northeast region to be divided according to east –west direction and
the height (figure 2.1). Topographic structure, interaction of terrain
circulation cause climate in the region to divide into climate patterns,
climates that have specific features. Factors of geology and terrain have
important influence on formation of the climate in the region.
- Factor group of hydrography - soils, vegetation cover are illustrated
in the figures 2.2, 2.3, 2.4, 2.5: Soil mantle - vegetation and hydrographical
factor have contributed to regulation of climate especially in area where there
is good soil, abundant hydrological reserves,high development of forest. So
this is the important factor of buffer surface affecting formation of climate
.The combined impact of buffer surface including terrain, soils, hydrography,
living organism and sea combined with factor of monsoon circulation on the
tropics has formed featured specific climate pattern and no other places in
the world at the same latitude have-11the similar feature. That is the humid
tropical monsoon climate with cold winter consisting of 3 cold months that
have temperature below 18ºC.
2.1.2. Factors of economy society - exploitation and rational use of
bioclimatic natural resources
By the end of 2012, population in Northeast region of Viet nam is
-119720.2000 (that belong to 30 different races),making up 11% of population of
the whole country. Most residents of the region live on agricultural and
forestry production (population in rural area accounts for > 80%).
Development of agricultural and forestry production will be the precondition
for economic and optimal employing surplus labours to contribute to
redistribution of residents, focus on development and improve living standards
of people in rural and mountainous area, exploit production and enhance the
quality of life for the communities in Northeast region.
* Economic sectors
- In the region a number of forest areas for materials used for
industry of processing paper,producing artificial board and, mine pillars
have been formed . That is why forest coverage has increased
significantly so far.
- Industrial sector of processing agricultural and forestry products in
the region í still limited in number and size. It í not associated with the
manufacturing sector. Procedures of product processing
rudimentary, having not been equipped with modern equipment. At the
present mainly primary products are exported to foreign markets at low
prices , . output in consumption of agricultural and forestry products is
not guaranteed so specialized activities of the production of goods face a
lot of difficulties
2.2. Laws of nature and climatic differentiation of Northeast region
2.2.1. General characteristic: Factors forming the climate have
specified general nature of the Northeast Climate: intrinsic properties of
tropics, monsoon, natural moisture, diversity and climate fluctuations.
2.2.2. Laws of climatic differentiation
Seasonal differentiation in climate of Northeast region is the most
important characteristic and has high practical significance, especially in
the field of production and economy of our country. Differentiation of
dynamics of seasonal climate here is due to the activities of monsoon
circulation, with a unique combination of geography..
The rules of the climate division include: differentiation of climate with
latitude, longitude, altitude and differentiated according to seasonal climate in
which climate rule of differentiation by elevation and seasonal are best
expressed in the differentiation of regional climate.
-12With rain regime, rainfall, humidity metioned above, Northeast
region is differentiated into areas with more rain, less rain very clearly.
Generally, it is favorable for the development of crops that prefer moist,
adaptive with distinct seasons. The distribution of rainfall over space and
time creates ecological diversity of crops..
The special weather phenomenon: In the region, the weather
phenomenon particularly like typhoon, local hot dry wind, frost, fog, hail,
thunderstorms, snow and ice ..etc… are the phenomena occurring with more
frequency and are harmful to development of vegetation covers and crops.
2.4. Mapping bioclimate of natural vegetation covers (based on
original source) in Northeast region of Vietnam
2.4.1. Establishment of principles of the bioclimate map of natural
Bioclimatic map that is established has to meet the following
principles: (i) The map must first reflect the climatic conditions of the
studied territories, differentiated according to time and space. (ii)
bioclimatic map must reflect ecological characteristics of the territory
containing models of vegetation covers available in the territorie studied.
(iii) bioclimate map must reflect the needs that serve for production,
planning territories studied.
2.4.2. Indicator system for bioclimates classification of vegetation
indicator system of heat and humidity being studied,and built for
bioclimatic map must meet the following requirements: (i) indicators
selected must be representative, that is, must reflect nature and distribution
characteristics of seasons, the hot season, the rainy season, by latitude,
altitude and season. (ii) indicators selected must reflect the nature of the
ecological climate, i.e, reflect the law of distribution, the growth and
development of certain types of natural vegetion covers on studied territory.
-System of heat includes average temperature of the year and
indicator of lenght of cold season
- indicator system of rain and wet including an indicator of total
annual rainfall and number of dry months is used for the climate type
-13-To sum up the criteria mentioned above, the bioclimatic map of
natural vegetation covers of the Northeast region is formed with heat and
wet indicator system (Table1).
2.4.3. The bioclimatic types of Northeast region
Table 1: indicator system of bioclimate of natural vegetation covers of
A – rain a lot
R year ≥ 2500mm
B - rain a
≤ R năm <
C – moderate rain
1500mm ≤ R năm <
D – litle rain
1200mm ≤ R year <
II – cool
III – L
E – litle
On the basis of analyzing the thermal and moisture divergence
indicators in the Northeast region combined with analysis of the distribution
of 6 types of natural vegetation covers in the studied area.The results of
classification show that in North East region, there are 6 t bioclimatic types
(described in Table 2) 20 different types of bioclimate of vegetation covers,
which have been repeatedly types on the territory of the studied area (116 of 20
separate zoning categories of bioclimate) are illustrated in the bioclimatic map
of natural vegetation covers of the Northeast region) (figure 2.13).
-14Table 2: Description of the types of bioclimate of Northeast region
type 1: bioclimatic type of tropical monsoon at lowland
area, which is a bit hot with a short, cold period , there is
lots of rain, dry season is from short to medium, including
the type of bioclimate IA1a and IA1b.
type 2: bioclimatic type of tropical monsoon at lowland
area which is a bit hot, cold period is short,there is
moderate rainfall, there are moderate to long dry seasons,
including the type of bioclimate IB1b, IC1b, IC1c.
type 3: Bioclimatic type of tropical monsoon, at lowland
area, it is a bit hot with a cic types ID1c, IE1c.
type 4: Bioclimatic type of tropical monsoon in low
mountainous area(500/600-1400m), it is cool, cold period is
average, there is very much rain to little rain. There are
medium to long dry seasons, including the type SKH IIA2a,
IIA2b, IIB2b, IIC2b , IID2b, IID2c.
type 5: bioclimatic type of tropical monsoon in area with
medium mountain (1400-2200m), it is cold, there is a long
cold period, there is a lot of rain to moderate rain, and
moderate short dry season, including the type of bioclimate
IIIA3a, IIIA3b, IIIB3b, IIIC3b.
type 6: bioclimatic type of tropical monsoon in high
mountains (> 2200m),it is very cold, there is a very long
cold period and a lot of rain, short to medium dry season,
including the bioclimatic types VIA4a, VIA4b, VIB4b.
Types of bioclimate that correspond
bioclimateic type of vegetation covers of
evergreen tropical rain forest.
This corresponds to the type of
bioclimate ofv egetation covers of semi
evergreen tropical rain forest
corresponding to the bioclimatic
type of vegetation covers of tropical
This type of bioclimate corresponds
to vegetation covers in climate of temperate
evergreen forest with lower moist
This type corresponds to vegetation
covers in climate of Moist Conifer and
Evergreen Broad-leaved Forest
This type corresponds to Alpine
vicinity (vegetation, the bioclimatic type of
vegetation covers in climate of high
mountainous area, cover types of coniferous
forest climate, which has dwarf trees
(Phyllostachys) in high mountain).
Bioclimatic types of tropical monsoon in the region include : (1) IA1a: bioclimatic type
with a bit hight temperature, there is a short cold time period, it is much rainy, dry season is
short. (2) IA1b of bioclimatictype with somewhat hot , there is a short cold time period, it rains a
lot, dry season is medium; (3) IB1b: bioclimatic type, which is somewhat hot , there is a short
cold time period, it rains a lot, dry season is long; (4) IC1b: , there is a short cold time
period,moderate rain and long dry season (5) IC1c: : bioclimatic type, which is somewhat hot ,
there is a short cold time period moderate rain and long dry season; (6) ID1c: : bioclimatic type
which is somewhat hot , there is a short cold time period, little rain,and long dry season; (7)
IE1c: bioclimatic type, which is somewhat hot ,cold time period is short ,there is little rain and
dry season is long; (8) IIA2a: bioclimatic type of low mountainous area,it is cool, cold time period
is long, it rains a lot, dry season is short; (9) IIA2b: bioclimatic type of low mountainous area, it is
cool, cold time period is long TB, , it rains a lot, dry season is medium; (10) IIB2b: bioclimatic
type of low mountainous area, it is cool, cold time period is average long , it rains a lot,, dry
season is moderate long ; (11) IIC2b: bioclimatic type of low mountainous area,it is cool, cold
time period is moderate long, it rains moderately,dry season is moderate long; (12) IID2b:
bioclimatic type of low mountainous area it is cool, cold time period is moderate long, there is
little raint,dry season is moderate long; (13) IID2c: bioclimatic type of low mountainous area, it is
cool, cold time period is moderate long, there is little raint,dry season is long; (14) IIIA3a
bioclimatic type of medium mountainous area, it is cold, cold time period is long, it rains a lot, dry
season is short; (15) IIIA3b: bioclimatic type of medium mountainous area , it is cold, cold time
period is long it rains a lot dry season is moderately long; (16) IIIB3b: bioclimatic type of medium
mountainous area, , it rains a lot, dry season is moderately long; (17) IIIC3b: bioclimatic type of
medium mountainous area, it is cold, cold time period is long, there is moderate rain, dry season
is moderately long (18) IVA4a: bioclimatic type of high mountainous area, , it is very cold, cold
time period is very long, it is cold throughout the year,it rains a lot and dry season is short; (19)
IVA4b: bioclimatic type of high mountainous area , it is very cold, cold time period is very long,
it is cold throughout the year,it rains a lot and dry season is moderately long; (20) IVB4b:
-15bioclimatic type of high mountainous area , it is very cold, cold time period is very long, it is cold
throughout the year,it rains a lot and dry season is moderately long.
In terms of area bioclimatic type IC1b makes up largest area of 20
categories (21832.22 km²), the second largest is the type IIC2b (10122.37
km²) The bioclimatic type SKH IVB4b accounts for the smallest area
(32.46 km²). Regarding the number of repetitions , type SKH IIC2b has the
most number of repetitions 36 times), followed by IIB2b, IID2b 10 times).
The other remaining bioclimatic types account for medium area and number
of repetitions is from 1 - 10 times. Characteristics of each bioclimatic type in
Northeast region are described in Appendix 3. Overall, the Northeast
bioclimatic resources are rich and diverse . On the studied area there are 20
bioclimatic types with different features. Biolimatic resources in the region
also have a clear differentiation based on the heat,. It is from hot, cool, a bit
cold to very cold . Rainfall in some places reaches over 4000mm/year (Bac
quang), some places raifall is less than 1200mm/year (Ky Cung River
Valley, Bang Giang), There is differentiation between the length of cold
season and between the length of dry season.
2.4.4. Bioclimatic mapping natural vegetation covers of Thai
Nguyen and Lang Son province and Sa Pa district of Lao Cai province
On the basis of bioclimatic map of natural vegetation covers in
Northeast region, based on the ecological characteristics of crops,
indicator system for classification of bioclimatic natural vegetation
covers, bioclimatic maps of vegetation covers.inThai Nguyen, Lang Son
provinces and Sa Pa district of Lao Cai provinces are determined and set
up in accordance with the ecological threshold of each selected crop for
assessment..Bioclimatic maps of Thai Nguyen, Lang Son on scale 1:100
000 (corresponding to 7 and 9 bioclimatic units) shown on figures 2.14,
2:15 and bioclimatic map of Sa Pa district of Lao Cai provine on scale
1:50 000 (10 bioclimatic units) (figure 2.16) are established as a basis for
the dissertation to assess bioclimatic adaptation for development of
industrial trees, medicinal plants mentioned in chapter 3.
2.5. Consistency and close relationships of cause and effect between
bioclimates of territory and distribution of natural vegetation covers
On being considered, the relationships between climate and
vegetation covers. in nature are easy to reccognize. With a certain
condition of climate and soil, a certain type of natural vegetation cover
will appear respectively. If there are the same bioclimatic conditions,
zonal soil type or non- zonal traits will inevitably generate, essentially
carrying the same characteristics, properties and processes. Generally
-16factors "bioclimate - vegetation - soil are regarded" as being unified in
general. That means in Northeast region of Vietnam may not appear
elsewhere characterized climate which is basically subtropical but forest
vegetation covers consist of tropical forest types  .Studying arising
and development of vegetation covers only based on soil, climate.
Ignoring climatic effects will lead to inaccurate results.
In fact, every bioclimatic type is characterized by a basic type of
vegitation cover. Type of vegetation cover arising will occupy a key area,
laying a gound for the layout orientation, development of economic
forests, agricultural crops and forest trees - the main object of the
production and help guide further study to serve for-production and
Subconclusion of chapter 2
1. Bioclimatic characteristics of Northeast region have been analyzed in
great detail. It shows that the Northeas region has typical climate:of tropical
monsoon climate with cold winter. Due to the influence of geological
structure, topography, circulation factor and sea, the climate differentiation is
in accordance with its own law. Bioclimatic map of the Northeast region of
Viet Nam on a scale of 1: 500,000 shows that there are 6 bioclimatic
types, 20 different bioclimatic types, with 116 separate zones. The map
also shows the rules of differentiation on territorial bioclimatic resources
of the Northeast region. It can be used as a basis for assessing adaptation
for bioclimate. Adaptation of bioclimate -resources for development of
agricultural crops and forest. Bioclimatic unit , bioclimate- soil resources
are selected as evaluation units. The bioclimatic maps at provincial level
and district level have been designed such as Bioclimatic map of Thai
Nguyen province (on scale 1: 100,000) with 7 bioclimatic units,
bioclimatic map of Lang Son province (on scale 1: 100,000) with
11bioclimatic units, the bioclimatic map of Sa Pa district (on scale 1:
50,000) with 15 different bioclimatic units. This is the basis for the author
toasess the level of adaptation of bioclimate-soil resouces in detail in
order to develop midland tea plants, llicium verum (Star anise), Black
cardamom metioned in chapter 3.
2. The contents of chapter2 also have elucidated the close
relationships, cause and effect between the bioclimatic conditions,
bioclimatic resources with formation, arising of natural vegetation covers
of the Northeast region. Close relationships between the climate system
and living organism is shown in the differentiation, the vegetation covers
that are differenciated by space, by elevation and through spectrum of life
-17forms of the main types of natural vegetation covers available on the
The results of study will be the suggestion for study, assessment of
bioclimatic resource for development of some agricultural crops and forestry
trees that have economic value, protecting natural conservation of natural
vegetation covers in Northeast region of Viet Nam
Chapter 3: ASSESSEMENT OF BIOCLIMATIC NATURAL
DEVELOPMENT OF A FEW AGRICULTURAL CROPS AND
3.1. Ecological characteristics of agricultural crops
* Acacia hybrid: Acacia hybrid is a tropical tree, which is adapted
to the temperature ranging 22-28°C. Requirements.The trees require
rainfall ranging 1200 - 2000mm/year.They can survive in dry season that
last from 3-4 months. The trees are capable of rapid growth, the roots are
strong, capable of retaining and improving soil, water regulation and
mixed cross breeding with many other tree species.
* Midle tea plans: Tea plant belongst osubtropical group of
plants,which is best adapted to temperatures between 20-28ºC. The plants
requires average annual rainfall ranging from 1500mm to 2000mm and
evenly distributed rainfall in the month. The tea plant requires high air
humidity, during the growth period appropriate air humidity ranging from
80-85%. The tea plants is adaptive to high terrain from 200 - 600m, less
than 15º slope. Soil for growing the tea plant has to be acidic. Its pHKCl
ranges from 4.0 to 5.5 with more than 1 meter deep soil and drainage..
*Illicium verum (Star anise): Illicium verum is adaptive to subtropical
climatic conditions of mountainous area. The tree requires annual average
temperature from 20-22ºC, cold winter but little frost, suitable raifall from
1200-1500mm/year. Illicium verum is less heat tolerant. Ảppropiate height
above sea level for growth of Illicium verum is about (200-600) m. The
Illicium verum likes good soil and fertile acidic soil with pHKCl from 4,0-5,5
and in soil layer with thickness of > 100cm.
* Black cardamom: The tree is originated from temperate and
subtropical areas, very adaptable to average temperatures between 1216ºC. At low temperature (below 10ºC) or high (above 22ºC) the tree
starts poorly developing and is no longer adaptive. Length of cold season
best adapted for cardamom is from 5-7 months. Cardamon particularly
likes moisture, requiring rainfall about 2000mm/year, air humidity in
-18forests from 85% to saturation, dry season length not exceeding 2
months.The worst conditions for cardamom is frost and snow, If this
phenomena occurs the tree will die.
3.2. Bioclimatic - soil map of Thai Nguyen, Lang Son provinces
(scale: 100.000) và and Sa Pa district of Lao Cai province (scale 1:
Map of bioclimate - soil resouces of Thai Nguyen province
designed consisted of 27 units of bioclimate- soil resources, Map of
bioclimate - soil resouces of Lang son province designed expressed 38
units of bioclimate- soil resources and Map of bioclimate-soil resouces of
Sa Pa district of Lao Cai province showed 33 units of bioclimate- soil
resources. Each unit of bioclimate- soil resources could be seen from
once to many times. Characteristics of bioclimate- soil resources units
are described in detail in the appendix.
3.3. Assessement of favourite level of climate and organizational
problems for development of agricultural and forestry production
3.3.1.The asessement critteria
Object selected for assesement of bioclimatic adaptation for
developing agricultural crops and forest trees t is the bioclimatic type unit of
bioclimate- soil resources. However, in order to evaluate the results more
accurately, the author used two groups of assessement criteria: Group key
criteria (the main factors): (mean annual temperature, mean annual
precipitation, length of the cold season, dry season length). This group was
applied for resource assessment for development of crops. Group of other
criteria (sub-elements):such as elevation, terrain slope, soil characteristics,
limiting climate factors: maximal temperature, monthly average temperature,
monthly average rainfall were used to assess.
3.3.2. Evaluation of results of bioclimatic adaptation in the
Northeast region of Vietnam for development of Acacia hybrid
Based on a Liebig's Law of the minimum (1840) and Shelford’ law
of toletance (1913), based on the ecological limitation and amplitude of
Acacia hybrid that is presented in the work of Le Dinh Kha (1999 ) and
forestry handbook (2004) on the distribution, ecology and growth of
planted forest to divide and determine the appropriate level for
developing bioclimatic type of Acacia hybrid. The author herselt has
evaluated as follows.
The resuls of the author’s own assessment of the ecological
requirement of acacia hybrid to bioclimatic conditions showed (figure 3.4):
The bioclimatic type of total rate adaptation was IC1b at highest elevations