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Proposed Applications for Conservation and Development of Five-Needle Pine Population


The results of the study showed that Kon Ka Kinh National Park is a suitable ecological area for 5-needle pine, with a wide distribution range.

Figure 3.44. Map of population density levels of 3-leaf pine in the Central Highlands. Density levels of 5-leaf pine: High (>100 trees/ha), medium (51-100 trees/ha),

low (10 – 50 trees/ha) and rare (<10 trees/ha)

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Figure 3.44 is a database of distribution and ecology of the 5-needle pine species in the Central Highlands, thereby helping managers and researchers identify the central distribution areas of the species or the fringe areas where the distribution is less abundant to propose appropriate conservation activities.

In addition, the distribution map of the population density of the 5-needle pine in the Central Highlands also helps to:

- Identify conservation areas for 5-needle pine, focusing on core areas with medium to high density levels (level N = 3 - 4);

- Identify areas with the potential to restore the Five-needle Pine population, focusing on areas with low to high density levels but already impacted (Level N = 1 to 4).

3.6. Proposed applications for conservation and development of the Five-needle Pine population

From the results of research on the forestry and ecological characteristics of the Five-needle Pine population, the thesis draws some important results that can be applied in the conservation and development of the Five-needle Pine population as follows:

i) Five-needle pine population model for conservation and development:

From the research results, some forestry and ecological characteristics corresponding to good populations are drawn as a basis for the conservation and development orientation of the Five-needle Pine population as follows:

- The dominant species structure includes broadleaf and coniferous species, of which 5-needle pine has an IV% of 4 - 12% in the forest stand.

- There is usually no regeneration of 5-leaf pine in mature populations, because 5-leaf pine prefers full light when regenerating. Therefore, it is necessary to promote regeneration of 5-leaf pine in areas where the canopy is broken due to the fall of mature trees.

- The N/D standard sample structure model of the forest stand has a reduced distribution of 5-needle pine trees simulated according to the distance distribution (Figure 3.45).


500

450

400

350

N (tree/ha)

300

250

200

150

100

50

0


67



469


425


169

27

11 4 2 1

11 21 31 41 51 61 71 81 91

D (cm)


Figure 3.45. Reduced standard sample N/D structure model according to distance distribution of forest with 5-leaf pine distribution

- The structure of the forest stand reaches random to even distribution when the average distance between trees is from 1.2 m to 1.7 m; in which for 5-needle pine, the optimal distance is from 6 - 7 m.

- In the population of the 5-needle pine species, the N/D distribution is mainly concentrated at the D level = 51 cm - 91 cm, meaning that the 5-needle pine does not have a continuous regeneration process on the same unit area, but will circulate in a streak regeneration style. The current populations have quite mature 5-needle pine, so promoting the regeneration of this species in gaps and circulation is necessary.

- The population density of the Five-needle Pine is governed by three main ecological factors: average annual rainfall, altitude and soil thickness. It is most suitable at an altitude of 1,500 - 1,900 m, with rainfall of 1,800 - 2,200 mm and a topsoil thickness of over 50 cm. The Five-needle Pine is not suitable for ecological regions with an altitude of less than 1,000 m, rainfall lower than 1,800 mm and a topsoil thickness thinner than 30 cm.

- The growth D of Pine 5 has a clear difference in three distribution areas: BD, CYS and KKK, which is well simulated by the Mitscherlich function D = 300 × (1 – e (-ai×A) ). In which, the growth of Pine 5 is most suitable for the KKK area, followed by CYS,


BD is the slowest growing place for D. Therefore, priority should be given to developing and conserving this species in KKK.

ii) Some specific approaches and techniques to support the conservation and development of the Five-needle Pine population:

- Approaching the mixed-age forest model in conservation and development of the Five-needle Pine population:

Five-needle pine does not grow purely like some other pine species such as three-needle pine, so afforestation and forest restoration with five-needle pine populations requires approaching the model of mixed-age forests.

The research results show that the 5-needle pine has a random relationship with the species of Chỏột, Dẻ đá (Oak) and has a positive relationship with the species Hồng quang; these are species that can be used for mixed forest planting or forest enrichment with the 5-needle pine in suitable ecological distribution areas.

- Planting mixed forests, promoting regeneration and enriching forests with 5-needle pine species:

During the regeneration stage, the 5-leaf pine prefers complete light, so planting a mixed forest of broadleaf trees and some conifers that have a supportive relationship with the 5-leaf pine is appropriate, but it is necessary to ensure the density to provide enough light for the 5-leaf pine in its young stage. For forest restoration such as promoting natural regeneration, enriching the forest with the 5-leaf pine species, it is necessary to identify gaps and planting ditches with enough light in the young stage of the 5-leaf pine. The best way to restore the 5-leaf pine population is to enrich the forest in patches and gaps in the forest, where mature trees fall and create large gaps that provide enough light for the 5-leaf pine seedlings to grow.

- Approaching forest structure with sustainable distribution of 5-needle pine population:

The reduced distance distribution model with its parameters estimated in this study according to ecological distribution areas provides the basis for establishing standard models in adjusting forest structure towards sustainability. In which, the distribution of 5-needle pine is not continuous, it can only be distributed in some age stages, at some diameter levels because of the mosaic cyclic regeneration characteristics of this species.


- Planning conservation areas and restoration of 5-needle pine populations:

It is necessary to rely on three ecological factors that have a comprehensive impact on the distribution density of the Five-leaf Pine species, which are altitude above sea level, rainfall and soil thickness to determine areas and ecological zones suitable for the Five-leaf Pine to conserve and restore the Five-leaf Pine populations. In which, the most suitable area for the Five-leaf Pine is where the rainfall is from 1,800 - 2,200 mm/year, at an altitude of 1,000 - 1,900 m above sea level and the soil has a fairly thick topsoil layer (> 50 cm) in the type of evergreen broadleaf forest mixed with conifers.

In addition, the increase in temperature due to climate change also affects the growth and development of the 5-needle pine. Therefore, afforestation and forest enrichment of this species requires silvicultural treatment in years with increased temperatures during the dry season, such as planting mixed forests and appropriate mixed density structures.

- Forecasting growth and yield of 5-needle pine:

The diameter growth model for 5-needle pine in the form of Mitscherlich Monomolecular): D = D m ×(1- exp(-a i ×t)) and the growth model P d = a×D bi changing according to each ecological distribution region i are the basis for predicting the growth and yield of 5-needle pine individuals and populations according to age and diameter class in planning the management and business of this species.


CONCLUSION, PROBLEMS AND RECOMMENDATIONS

CONCLUDE

1. Structural characteristics of forest stands with distribution of 5-needle pine in the Central Highlands

The tree species composition of the forest stands with the distribution of 5-leaf pine in the Central Highlands has a dominant number of species from 5 to 8 (with IV% ≥ 3%), in which 5-leaf pine is always the dominant species with IV% from 3.6% to 12.2%. The dominant regenerated tree species composition fluctuates from 4 to 7 species (with IV% ≥ 3%), 5-leaf pine has very rare regeneration in forest stands with mature mother trees, while 5-leaf pine has very strong regeneration in open areas; showing that 5-leaf pine has a cyclic regeneration pattern along the open canopy.

The N/D distribution law mostly follows the general distribution law of tropical mixed forests and can be simulated according to the distance distribution (in the form of an inverted J or a peak at the small D level). The N/H distribution is very variable, with one to many peaks from left to right and changes according to each ecological condition, so it is difficult to approach according to a general distribution law. The surface distribution of the forest stand is mainly clustered in the middle-aged stage, gradually changing to random when it begins to mature; in which, considering the species of 5-needle pine, most of them have clustered distribution, meaning that 5-needle pine only regenerates through holes and cycles, so it often has a cluster distribution in streaks.

The N/D and N/H distribution of the 5-needle pine population alone has one to many concentrated peaks, because there is no continuous regeneration but only regeneration in certain favorable stages on the same unit area.

2. Influence of ecological factors on the density distribution of 5-needle pine trees

Five-needle pine is distributed in evergreen broadleaf forests mixed with conifers, and density (N) is influenced by major ecological factors such as altitude (DC), soil thickness (TDD) and average annual rainfall (P) through the model N = P × (0.890614 × DC -0.0451131 × TDD 0.540172 × P -0.9126 )

3. Ecological relationship between 5-needle pine and ecologically dominant species in the population


Five-needle pine is a species that has a random relationship with the species Chỏ tít, Dẻ đá and has a positive relationship with the species Hồng quang. In the regeneration tree layer, Five-needle pine has a positive relationship with the species Chỏ tít and has a random relationship with other ecologically dominant species.

4. Influence of climate factors and distribution areas on growth and development of 5-needle pine

Climatic factors affecting the growth of 5-needle pine: i) In cold regions such as Lam Vien plateau, increasing temperature during the rainy season promotes the growth of 5-needle pine; ii) In less cold regions such as Buon Ma Thuot and Pleiku plateaus, increasing temperature during the dry season reduces the growth of 5-needle pine.

The growth model for the 5-needle pine species was established and cross-validated for three ecological distribution regions (Bidoup - Nui Ba, Chu Yang Sin and Kon Ka Kinh), with the H/D relationship in the Power form, with the diameter growth model D/A in the Mitscherlich function form D = 300×(1 – e (-ai×A) ) and the diameter growth rate Pd/D in the Power form with negative exponential parameters: Pd = a×D bi , in which the parameters a i and b i vary according to the ecological distribution region i.

5. GIS database on density distribution and ecology of 5-leaf pine

A GIS map of the population density of the Five-needle Pine has been built along with data on 10 ecological factors in the Central Highlands to help determine the concentrated distribution area of ​​this species for conservation management and restoration of the Five-needle Pine population.

6. Application of research results

From the research results, the applications in conservation and development of the 5-leaf pine population have been synthesized, including: i) The 5-leaf pine population model oriented for conservation and development; ii) Some specific approaches and techniques to support the conservation and development of the 5-leaf pine population such as: Approaching the mixed forest model in the restoration and conservation of the 5-leaf pine population; Planting mixed forests, enriching the 5-leaf pine forest; Building standard forest models; Planning conservation areas and restoration of the 5-leaf pine population; Predicting the growth and yield of the 5-leaf pine.


EXIST

Due to limitations in time and resources, the thesis still has some shortcomings.

at the following:

1. There has been no survey and data collection in areas with natural distribution of the Five-needle Pine species such as Ngoc Linh Nature Reserve, Tu Mo Rong district and neighboring areas of Kon Tum province; at some other locations in Bidoup - Nui Ba National Park and neighboring areas of Lam Dong province and other areas in Chu Yang Sin National Park, Dak Lak province.

2. Climate data is collected generally for each region and area and is not specific to different ecological sub-regions, altitudes, and terrains in each region.

3. The GIS map of the population density of the Five-needle Pine after construction has not been verified for errors in the field.

PROPOSAL

To overcome these shortcomings, the thesis recommends continuing to collect data in most areas with natural distribution of the 5-needle pine species in the Central Highlands and conducting:

1. Further research on the influence of climate factors and changes in climate factors on growth, to determine the appropriate or inhibitory climate threshold for the growth and development of the 5-needle pine species.

2. More detailed research on ecological factors such as light, temperature, and forest fire affecting the regeneration of the 5-needle pine species.

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