+ In terms of practice, - It is based on a clear analysis of causes affecting the sustainability of forest ecosystems; solutions for sustainable development are proposed to contribute t
Trang 1Thai Nguyen University
-
NGUYEN ANH HUNG
Studying on human affects on the sustainability of
forest systems in the atk - safety zone
in dinh hoa district, Thai Nguyen province
ABSTRACT OF Ph.D dissertation IN biology
THAI NGUYEN, 2013
The thesis is fulfilled at
Trang 2Scientific supervisor:
1 Dr LE HONG TAN
2 Prof Dr Sc TRAN DINH LY
Opponent 1: -
Opponent 2: -
Opponent 2: -
This dissertation will be reported to the National Thesis Reviewing Board of Thai Nguyen University held at………
at … h……….the …… day of ………., 2014
This dissertation can be found at
- THE NATIONAL LIBRARY
- LEARNING RESOURCE CENTRE – THAI NGUYEN UNIVERSITY
- THE LIBRARY OF UNIVERSITY OF EDUCATION – THAI NGUYEN UNIVERSITY
Trang 4FOREWORDS
1 Background of the study
Forest is an extremely valuable natural resource to the countries In fact, the value of forests is not only a basis for socioeconomic development, but also has many important ecological functions It involves in the processes of climate regulation and limits the damaging effects of floods, drought, soil protection, etc In addition, value of
forests also creates landscapes of tourism, and scientific research
Currently, the demand of natural resources of the human is increasing more and more leading to many conflicts in the relationship between natural conservation and development To resolve this conflict and to meet human needs in a sustainable way, the natural resources and especially forest resources should be used efficiently
The government has issued a series of policies encouraging the resident communities to receive land, forest for cultivation, protection, raising zoning and enactment of forest protection and development, decrees and directives on the management of forest fires, establishment, strengthening forest rangers, building a forecasting network of forest fire in provinces However, the capital investment in many localities is limited and the deforestation still occurs frequently Immensed wind The ATK-Safety Zone located Dinh Hoa district, an abundant wind capital in resistance against the French, includes 23 communes and towns The reasons that Dinh Hoa was chosen as the revolutionary base, are due to rugged terrain, dense forest with canopy levels to ensure confidentiality Today the war has gone, under the impact of market mechanisms and the various reasons, the forest ecosystems have been destroyed Therefore, in order to demonstrate the ethical issue “when drinking water, remember its source” and to express the concern of the Party and Government for residents in the ATK-Safety Zone, the State has also invested to socio-economic development Currently, the lives of people in the Safety Zone has been improved, but still coupled with many disadvantages Residents in the studied area have still exploited forest resources to ensure their livelihood and the plant cover continues to suffer from exploitation For above reasons, I chose the subject of my doctoral thesis
Trang 5is: "studying on human affects on the sustainability of forest ecosystems in the Safety Zone in Dinh Hoa district, Thai Nguyen province"
ATK-2 The objectives of the study:
- Researching and evaluating the current state of forest ecosystems in the studied area
- Assessing human impact related to sustainability of forest ecosystems
- Proposing solutions for management and sustainable use of ecosystems in the Safety Zone of Dinh Hoa, district, Thai Nguyen province
ATK-3 The scientific meaning and practice of the dissertation
+ In term of reasoning,
- Through the scientific evident materials, the relationship between the human’s livelihood activities impacting on forest resources in particular and the ecosystem in the studied area in general has been clarified
- The results of the dissertation are reference materials for specialized teaching activities in universities
+ In terms of practice,
- It is based on a clear analysis of causes affecting the sustainability of forest ecosystems; solutions for sustainable development are proposed to contribute to the protection of the ecological environment in the studied area
- Solutions provided from the dissertation contribute to improvement of the lives of people in the studied area and reduction of pressure on forest resources
4 New contribution of the dissertation
- Studying the role of the forest ecosystem in protecting landscapes for the historical - cultural relic in the studied area
- Researching on effects and role the human in the management and sustainable exploitation of the forest ecosystem serving socioeconomic development
- Providing quantitative evidences in systematic to prove the relationship between the human activities of livelihood and the sustainability of forest ecosystem in the ATK-Safety Zone
Trang 6Chapter 1 LITERATURE REVIEW 1.1 Some concepts
1.2 The history of human impact on the ecological environment
1.3 Issues on sustainable management and use of ecosystems
1.4 The main research trends on forest ecosystems
1.5 Trends in research on human impact on the forest ecosystems
Chapter 2 SUBJECTS, CONTENTS AND METHODS OF STUDY 2.1 Subjects of the study
- Forest ecosystems in the Safety Zone in Dinh Hoa district, Thai Nguyen province
- The impacts of human’s activities to the sustainability of forest ecosystems in the ATK-Safety Zone in Dinh Hoa district, Thai Nguyen province
2.2 Research Contents
- Researching on natural and socio-economic conditions in the studied area; studying the diversity of the flora and plant cover in the studied area; surveying study on human’s affects on the forest ecosystem in the studied area; assessing impact of the impacts on the forest ecosystem; studying to propose solutions for sustainable development
2.3 Research Methodology
2.3.1 Reasoning method
- Accessing to humanity ecological approaches to the study of the relationship between the natural system and social system in the exploitation and sustainable use of the forest ecosystem
- Inheriting existing statistics, adding and updating information required Using the investigating method of the involvement of residents through interviewing people, leaders at all levels, the forest officials at the localities, etc
2.3.2 Survey Method
2.3.2.1 Method of route survey (RS) and standard plots (SP): We use the method of
Hoang Chung (2008) and Nguyen Nghia Thin (2008)
2.3.2.2 Methods of data collection
+ For plants
- Measuring the diameter at breast height (1.3 m above the ground - D1.3 cm) by glasses caliper gauge with mm accuracy and measured in both directions from the Northeast to Southwest, and then calculating the average value; Measuring total high tree (THT, m) Trees are under 4m high and are measured by a rod with divided line and dm accuracy Trees are over 4m high and are measured by Blumeleiss according
to the trigonometric principles Total high trees are determined from stumps to the growth top of tree
Trang 7- Investigating regenerated trees: In the standard plots, 5 plate format cells created have an area of 25m2 and distributed evenly on the standard plots There is statistics of names of species If species are unknown, specimens collected for identification A rod with quality assessment of regenerative trees measures height of regenerative tree Potential tree group is the trees available a height of 1.5 m, a good vitality, the competitive ability with the tier of shrubs and fresh vegetation, straight stem with evenly canopy; trees harmed by animals eating or trampling It is expressive bruised trees, broken branches and loss of the young shoots
- Identifying the canopy cover percent (CCP) with a spherical mirror
+ For the soil samples: Soil samples taken according topoint method, on a sunny day
in the patterns of vegetation covers: Land of the secondary forest, land of shrub vegetation land, grass hilly land, land under planted forest canopy at a depth of 0 -10cm to analyze of soil microorganisms and at a depth of 0-15cm to analyze thephysical and chemicalindicatorsofsoil
2.3.2.3 Method of Interview Survey
- Survey method of resident communities:in each commune, itsurveys 10residents as representatives for householdersworkingwithforestry productionactivities
- Expert method: workshops are organized with the participation of the forestrial
officials, scientists, local managers in order to evaluate the survey results and survey results and comments to complete the suggested solutions
2.3.3 Methods of analysis and data processing
+ For plants
- Identifying the scientific names of plants according to the document of the author Pham Hoang Ho (1993), a Plant List of Vietnam (2003, 2005)
- Determining life forms and the use value of the plant species-based the document
"Names of Vietnam forest trees" and "1900 useful plant species of Vietnam"
- Identifying rare plant species based on documents the Vietnam Red Book 2007 - The Flora part and the Decree 32/2006/ND-CP of the Government; the Red List of Medicinal Plants in Vietnam in Handbook of medicinal herbs required protection
- Vegetation Classification: It is based on UNESCO's classification (1973) for the classification of vegetations
- Determination of the group of high tree tier under following the formula:
%IVi
=
%Ni + %Gi
2 Where:% IVi is the percentage of group of species i % Ni is the total tree number of species i
% Gi is total basal area of species i
- Identifying the canopy cover percent (CCP): Use of spherical mirrors to conduct measurements at five different positions in standard plots (SP), then added up numbers and divided by the number of numbers to find mean of canopy cover percent under the
Trang 8following formula:
CCP =
N x 1.4
100 Where N is the number of square plots covered in a spherical mirror
- Determination of biomass of dead vegetation: the method of Kurniatun et al (2001) is applied Volume of dead vegetation on the ground is determined by weighing dead vegetation square cells with the area of 1m2 and each vegetation status is repeated 12 cells
+ For the soil samples:
- Determining the number of microorganisms under the limiting dilution method on orientation-selected medium; active of cellulose resolution under the agar diffusion
method and measurement of resolution circles on agar plates; Determining microbial
diversity by means of morphology, physiology and biochemistry; Identifying bacteria components according to Bergey's classification 1974, Yarrow’s classification of the yeasts 1998, the classification of fungi and Hunter 1995 Bernett, Babieva’s
classification of Lipomyces yeast 1987
- Identifying pHKCl measured by pH meter; Determining humus (%) by Tiurin method; Determining total protein content (N%) according to Kjeldahl method; Determining total phosphorus (P2O5%) by the method of Atomic Absorption Spectroscopy (AAS); Determining total potassium content (K2O%) by the method of emission spectra; Identifying proportion by Picnomet method; Identifying density by the density tube
method, Determination of porosity by the formula: P (%) = (1 - D/d) x 100 (P - porosity
of the soil (%), D - load-bearing capacity of soil; d - bearing capacity of soil);
Determining moisture by the method of absolute drying in drying cabinet
- Determining thickness of topsoil eroded by pilling; Determining the soil-loss amount (tons per hectare per year) according to the equation of Wischmeier W.H and Smith D.D.:
A = R*K*L*S*C*P, of which,
R is the rain factor Calculated method of Nguyen Trong Ha is used by the formula:
R = 0.548257 P - 59.9 (P is mean annual rainfall); K is the coefficient of soil erosion, use of a K – input lookup tables corresponding to each soil type according to studied result of Nguyen Trong Ha; exponential ranged coefficient L is the slope length coefficient with L = (X/22.13)m, (X is the slope length (m), m is the exponential
Trang 9ranged coefficient from 0.2-0.5, m = 0.2 if slope is ≤ 1%, m = 0.3 If the slope is from 1% - 3%, m = 0.4 if the slope is from 3% - 5%, m = 0.5 If the slope is ≥ 5%), S is the slope coefficient with S = 65.4 Sin2 (x) + 45.6 sin (x) + 0.065 (x is the slope (in degrees)) C is the cover-coefficient and an C-input lookup coefficient use d corresponding to each vegetation as a result of research of Nguyen Ngoc Lung and Vo Dai Hai P is the coefficient of soil protection work and P = 1 due to without any measures and erosion control works
Chapter 3 NATURAL AND SCIO-ECONOMIC CONDITIONS
- The flow system of rivers and streams: Due to geological structures under the northwest - southeast direction and interspersed terrain of hills and rocky mountains, creating the system of river and streams distributed fairly evenly over the territory with the rich and plentiful water source The territory of Dinh Hoa district is the headwaters
of streams and tributaries of streams and forms 3 systems
3.2 Socio-economic conditions
The ATK-Safety Zone of Dinh Hoa district includes 24 administrative units including 23 communes and 1 town with a total area of 52272.23 hectares Ethnic communities living in Dinh Hoa district consists of 8 ethnic groups, of which, it is mainly ethnic groups of Kinh, Tay and Nung and the remaining ethnic groups account for low proportion (San Chi, Dao, Cao Lan, H 'mong and Thai groups) Dinh Hoa district's population is 87,722 people with the average population density of 171
Trang 10people per km2 In rural areas, there are 80,144 inhabitants accounting for 92.97% of the district demographics This shows that the population is mainly concentrated in rural areas and depends mainly on agriculture and forestry production Currently, the rate of natural increase of population tends to increase that causes pressure on forest resources
Chapter 4 RESEARCH RESULTS AND DISCUSSION 4.1 The current status of forest resources in the studied area
4.1.1 The current status of use of forestrial land
The area of forest land of Dinh Hoa district is 35787ha and accounts for about 70%
of the total natural land area In particular, there are 24.792ha of forest land, accounting for 69.3% of the total forest land area and 47.4% of the total natural land area; the land area without forests accounts for the lower proportion and is 30.7% of total area of forest land, including current forest states is IA, IB, scattered bare hills, etc
4.1.2 Vegetation characteristics
4.1.2.1 The vegetation types: According to the UNESCO classification (1973), in Dinh Hoa district, there are vegetation types as follows: the closed forest formation,
sparse forest formation, shrub forest formation and grassland formation
4.1.2.2 Flora characteristics: It is initially to record 636 species in 401 genera, 126
families and 5 branches of vascular plants
4.1.2.3 Rare plant species: Detecting the 50 rare plant species listed in the Red Book
of Vietnam, Decree 32 of the Government and the Red list of medicinal plants
4.1.2.4 Use value of groups of forest resources: Statisticing 10 groups of use value of
plant species Of which, the most tree groups are used and exploited are groups of trees for timber, medicinal plants, edible plants, trees for building materials, plants for arts and crafts and cattle feed crops
Trang 114.2 The role of forest ecosystems
- Conservation of biological diversity
- Protection of land environment and water resources
- Protection of landscape and the historical and cultural relics
- Ensurement of socio- economic development
4.3 The human’ activities affecting forest ecosystems
4.3.1 Negative activities
4.3.1.1 Activity of shifting cultivation: The highest rate of shifting cultivation is San
Chi ethnic minority, then the rate of shifting cultivation of Dao ethnic group accounts for lower rate and after that to Tay ethnic group and other ethnic groups Formerly, in order to have the area for cultivation, the natural forest area burnt and destroyed is quite large Currently, due to work in effective advocacy and education for ethnic people in sedentary farming settlement, activity of shifting cultivation is no longer active However, areas used and cultivated by people are abandoned so far, it has to
wait for very long time to recover its initial existing forests state
4.3.1.2 Deforestation for planting tea: To expand tea planted area, residents have to
destroyed the palm tree forests and Neohouzeaua forests inherited from their previous generations or even from natural forests Through investigation, it showed that 72.37% of the currently tea planted land is derived from forests inherited from their parents It includes forest kinds such as the mixed forest available palm trees + woody plants + Neohouzeaua, the forests of palm trees or forest of Neohouzeaua and small bamboos
4.3.1.3 Activity grazing livestock: current cattle are grazed mainly in the forest It is
very limited to graze in the grass fields around the fields and gardens Therefore, affect
to forest vegetation is also significant
4.3.1.4 Activity of timber exploitation: timber operations used in 2 purpose is to sell and use in the family, in which, a number of participants getting wood for domestic
use is lower than that for sale Activity of timber exploitation for sale occurred the
most powerful activity in the period of 1990-1995, the illegal timber exploitation is
mainly and the wood reserve decreases the most sharpness
4.3.1.5 Exploitation of non-timber forest products: use value of non-timber forest products
that gives people a lot Therefore, residents of Dinh Hoa district always consider that forest
Trang 12is a warehouse in which, there is everything to serve people's lives and activities of exploitation of non-timber forest products are still taking place in the studied area
4.3.2 The positive activities
Compared with the activities that negatively affect forest resources, these positive activities are not much Some positive activities are afforestation activity, zoning promotion of regeneration, restoration of relics to create a new landscape and management and protection of forest resources
4.4 Influence of impacts on the sustainability of forest ecosystems
4.4.1 The decline in biodiversity and qualities of regenerated plants
* Affect regenerated plants qualities: Wherever, the higher the density of the grazing
is, the lower the density of regenerated trees is, the lower the rate of potential trees is and the more the proportion of trees harmed by cattle is Thereby, these cause major obstacles for forest regeneration process
* Depletion of plant resources
* Declining Animal Resources
4.4.2 Destruction of the forest ecosystem structure
Because the history of human impact on vegetation covers in in the studied area took place in a very long time, we cannot observe in a comprehensive manner in duration of implement of this study Therefore, in order to the structural characteristics
of forests, we replaced time by space
To evaluate the change in structure of forest ecosystems, study sites chosen by us are the patterns of vegetation covers such as the natural forest pattern on soil mountains, human-impact secondary forest, scrub vegetation and greensward These vegetation pattern are derived from primeval forests due to overexploitation of human
- The pattern of forestland on the soil mountain has only the 4-storey structure Its stratification may appear obvious and botanical species composition is relatively stable, wood tree species have qualities in good and average levels
- It is the pattern of human-impact secondary forest due to significant human impact and vegetation patterns are changed Currently, vegetation pattern is recording at the period of 10-15 years and average height is still low There is only the 3-floor structure Tree species available good and average qualities are not much Most of
Trang 13them are light favorite species and fast-growing trees with low economic value The change of groups to become species in the vegetation floors is in progress and instability in terms of the structure
- For the pattern of shrub vegetation and greensward, there is only a 2-storey structure The origin of these patterns is mostly formed by uncultivated milpa Currently, forests are recovering at an early stage Therefore, the floor structure is relatively simple Therefore, groups becoming species in two vegetation patterns are mostly short-lived species and light favorite trees and appropriate for poor soil conditions
4.4.3 Degradation of environmental land
* The impact of the coverage of vegetation on some soil physical properties
It is based on the data table 4.28, we found that indicators on density, volumetric weight, moisture content and soil porosity under patterns of vegetation covers are different In particular, density (from 2.43 to 2.63 g/cm3) and volumemetric weight (from 0.79 to 1.20 g/cm3) of land reduce gradually from greensward the scrub vegetation the planted forest the secondary forest or in other words, the higher the coverage of vegetation is, the lower the soil density and volumetric weight are
For the soil available high density and volumetric weight, root systems of plants growing in the soil usually have poorly developed and are less likely to deep into the soil So that, on the soil of greensward and scrub vegetation, species are mainly limited reproductive Thus, the density and volumetric weight are closely related with the coverage of vegetation covers In addition, it also directly related to soil structure, soil eroded capabilities, soil fertility, etc
Table 4:28 Some physical properties under vegetation covers
Trang 14vegetation greensward or in other words, the higher the coverage of vegetation is, the higher porosity and moisture of soil are Humidity and porosity of the soil under vegetation covers of the secondary forests and natural forests is high due to the large coverage (see Section 4.2.2) Besides porosity and humidity are closely related to the volumetric weight and density in the same land sample The lower the density and volumetric weight are, the higher the porosity increases Thus, increase of water infiltration into the soil leads to increase soil moisture, while soil erosion is also limited
* Affect of the coverage of vegetation on soil erosion
Coating of vegetation types plays a very important role, is effective in soil erosion control To determine the extent of soil erosion in different forest states, we conducted
a survey, analysis, statistical results showed in Table 4.29
Table 4.29 Soil erosion in vegetation covers Kinds of land under
vegetation covers
Thickness of eroded soil (mm per year)
The amount of soil eroded (tons per ha per year)
Manglietia glauca planted forest 2.1 20.7
Thus, the highest level of soil erosion under vegetation patterns is in order the greensward > the scrub vegetation > the planted forest > the secondary forest This means that the role of the coverage of vegetation patterns for erosion control is very significant The greensward and the shrub vegetation have low coverage, lower soil porosity and less falling object mass (see Section 4.2.2), Therefore, the possibility of large erosion In the Manglietia glauca planted forest, although coverage is great, this
is pure forest, under the fresh vegetation layer with thin canopy, erosion has still occurred Meanwhile, the secondary forests have high coverage, fresh and mildewed vegetation under thick forest canopy, soil available the most porosity that decreases surface flow and mobility of the soil particles, limits erosion
* Affect of the coverage of vegetation on some chemical properties of soil
The results in the table 4.30 show that nutrient content of soil increases gradually from greensward scrub vegetation panted forest the secondary forest or in other words, the higher the coverage of vegetation is, the greater the level of nutrient content is