GOALS AND OBJECTIVES
Goals
- Construct the model for the mixed forest with the indigenous species:
Erythrophleum fordii understory of the timber tree: Pinus massoniana at the experimental forest in Luot Mountain
- Using some silviculture practices to help the experimental forest to develop with regenerate direction.
Specific objectives
- Make comments on the relationship between the qualitative change of the parameters with the growth and regeneration of indigenous species and timber tree
- Assessment the actual situation of mixed forest pattern, which have two species are
Pinus massoniana and Erythrophleum fordii at the experimental forest on Luot
- Assessment the potential growth and the affect on the growth of indigenous species to growth ability and regeneration of Pinus massoniana species on the research areas
- Give some silviculture practices impact on the timber trees to create good conditions for the timber tree to growth and regeneration better
METHODS
Desk research
Conducting set up the standard plots (SPs) to investigate and determine the number and quality of the trees in the research areas.
Field works
1.2.1 Set up standard plots method
Utilizing topographic maps and a handheld compass, we initially investigated all research areas to accurately locate objects on the map This process involved documenting forest conditions, particularly where indigenous species thrive beneath the canopy of other trees, to identify suitable locations for establishing standard plots.
Establish three standard plots, each measuring 1000 m² (25m x 40m), strategically located in areas rich in indigenous species Ensure that the plots are oriented parallel to the contour lines to enhance ecological monitoring and conservation efforts.
8 width perpendicular to contour line It set up to investigate the indigenous species and timber tree
- Then, set up the sub-plot (2m*2m), there are 5 sub-plots in each standard plots It is set up to investigate the situation of shrubs and vegetation
1.2.2 Data collection a Investigation the indigenous species and timber tree
+ Investigation and collect the data all of tree in the research areas (include the indigenous species and the timber tree
+ Conducting: choose the trees in standard plots
+ Determined to the DBH at 1.3m from land surface by caliper follow 2 directions: E-W and S-N, calculate the average of them
+ Determined the height of the peak-trees by blume-leiss
+ Determined the tree crown in 2 directions: E-W and S-N and estimate the average of them
+ Determined the timber tree canopy cover by the method of estimating the percentage of light concealed by trees
+ Survey and description of morphological characteristics, level growth of forest trees and classify the tree’s qualities
+ Evaluate the quality of the tree
1 A good tree (high quality): the vigor tree, not damaged by pests, the canopy balance
2 Normal tree (average quality): the tree growth is normal, tree form less than good tree, the growth of canopy in average level
3 Bad tree (low quality): the tree has capacity growth is low, pests, loss peak, the canopy and body of tree imbalance
- In each standard plot to set up 5 sub-plot have areas is 4m 2 /sub-plot, 4 sub-plot at 4 corner and 1 sub-plot at the mid of standard plot
- In each sub-plot, we conduct to identify the main tree species, average height, ground cover and the growth situation of shrub and vegetation
- Investigation shrubs, vegetation layers: Shrubs are woody plants have low layer
- The targets identified: name, quantity and height of species
- After data collection, we conducted using the Excel software to data processing Identifying the density of N species by the formula:
N N0 is the average number of the trees in investigation plots
S0 is the areas of investigate plots
+ Statistical indicators investigation of indigenous trees for each species in each plot + Description the morphology and ecology characterize of the species
+ Calculate the average of growth index: DBH, height, diameter of canopy, peak-tree height for each species in the investigations unit
+ Statistical rate the tree-number according to the quality of the tree
+ Comments relationship between the growth of indigenous species and the factors: canopy cover of the high canopy layers, shrub, vegetation
+ Calculate the average value of tree high canopy in plot
+ Up to a size distribution of trees in diameter (N/DBH) and tree distribution follow the height
+ Statistic the ratio of the number of tree according to the quality of species
+ Calculate the average value of the height and quality of trees in the each plot.
RESULTS AND DISCUSSION
RESULT
1.1 The actual situation of timber trees.
The main species of timber tree on research areas is Pinus massoniana
Table 1.1: Data compilation of timber trees
Total n (trees/plot) N (tree/ha)
1.1.1 The average height of timber trees(m)
Figure 2: The distribution chart of species follow the height of Pinus massoniana
- Through the data processing on the growth of tree-height at research areas shown that: The height average of Pinus massoniana at 3 standard plots alternate are: 15.2(m),
The Pinus massoniana forest has reached a mature stage, with an average height ranging from 16.0 to 16.9 meters The growth capacity of tree height among the species in the research areas shows no significant differences However, the distribution of tree heights reveals considerable variability, with measurements fluctuating between 13 meters and 25 meters.
1.1.2 The D 1.3 of timber trees(cm)
- Through the collecting and processing data of diameter growth of Pinus massoniana, it shown the result as follows:
Figure 3: The distribution chart of species follow D 1.3(cm) of Pinus massoniana
- Through the processing data about diameter growth of Pinus massoniana at 3 standard plots, it shown that: the D 1.3 of Pinus massoniana in 3 standard plots are:
22.0(cm), 18.9(cm), 22.4(cm) Look at the figures 3, there are too many individual of
Pinus massoniana have large D 1.3, that mean Pinus massoniana forest has entered the maturity stage
1.1.3 The average D (crown-canopy) of timber trees
- Through the table 1.1, it shown that the average Dcrown-canopy of Pinus massoniana on 3 standard plots are small(alternate are: 3.68(m), 4.25(m), 4.51(m)) The growth of
14 average Dcrown-canopy is conveniently ratio with the ability to shade for indigenous species understory timber trees All of them on research areas have the grow ability of average
1.1.4 The quality of timber trees(Pinus massoniana)
Table 1.1 indicates that the majority of Pinus massoniana species in the research areas exhibit average to low quality, comprising 50% to 80% of the total tree population Conversely, approximately 40% of the trees demonstrate high quality and good growth This low growth ability is attributed to significant competition from other species within the research areas.
1.2 The actual situation of indigenous species
- The main species of indigenous species on research areas is Erythrophleum fordii
Table 1.2: Data compilation of indigenous species:
1.2.1 The average height of indigenous species
Figure 4: The distribution chart of species follow the height of Pinus massoniana
- Through the table 1.2, the average height of Erythrophleum fordii species of the at
The three standard plots, measuring 13.9m, 16.0m, and 13.4m, indicate that the indigenous species is experiencing significant diameter growth, with average heights ranging from 12m to 18m, demonstrating strong growth potential However, as illustrated in Figure 4, there is considerable variation in tree height across the standard plots, fluctuating between 11m and 22m, highlighting the uneven growth patterns of these indigenous species.
Figure 5: The distribution chart of species follow D 1.3(cm) of Erythrophleum fordii
The data collected from three standard plots reveals that the average diameter of Erythrophleum fordii species is 12.82 cm, 12.92 cm, and 14.00 cm, indicating relatively small diameters that limit their exploitation due to low wood volume As shown in Figure 5, the majority of individuals have an average diameter ranging from 11 cm to 17 cm, suggesting that these trees are in a growth phase where they require increased nutrients to enhance both diameter and height.
1.2.3 The D (crown-canopy) of indigenous species.
- Through the table 1.2, it shown that the average of crown-canopy diameter of
Erythrophleum fordii species at 3 standard plots is normal (alternate are 4.19(m), 4.70(m),
4.80(m)) General, the ability growth about crown-canopy diameter of Erythrophleum fordii species is very good Because of them have good condition when they live understory of the timber trees
1.2.4 The quality of indigenous species
Table 1.2 indicates that the Erythrophleum fordii species demonstrates robust growth in various research areas, with approximately 50% to 60% of individuals exhibiting high quality Additionally, the population of trees with average and low quality is minimal, and the quality of individual trees is consistent, showing little variation.
1.3 The situation of other species on research areas
- Some information of other species growth on research areas
Table 1.3: Some species grow on plot 1
Table 1.4: Some species grow on plot 2
Table 1.5: Some species grow on plot 3
The three standard plots exhibit healthy growth across all species, with no presence of undesirable trees The average tree height ranges from 14 to 22 meters, while the average diameter measures between 15 and 22 centimeters, indicating that the trees are in a mature stage The dominant species in these plots include Cinnamomum parthenoxylon, Eucalyptus camaldulensis, Dracontomelon duperreanum, Manglietia conifera, Acacia auriculiformis, and Peltophorum pterocarpum.
In the research areas, various understory species thrive under the Pinus massoniana, with some exhibiting superior growth and strength, thereby fostering a favorable environment for other plants However, the robust growth of these understory species can adversely impact the development of timber trees and indigenous flora.
1.4 The situation of shrubs and vegetation on research areas
Table 1.6: Shrubs and vegetation on the 3 standard plots
Plot Main species H Cover (%) Quality
The primary shrub and vegetation species identified in Plot 1 include Calamus tonkinensis and Callipteris esculenta In Plot 2, several areas consist of bare land and grass, with three out of five sub-plots featuring species such as Solanum thruppil and Callipteris esculenta Plot 3 is dominated by Calamus tonkinensis, Callipteris esculenta, and Ageratum conyzoides, with occasional sightings of Amorphophallus paeoniifolius in one sub-plot The remaining sub-plots are primarily characterized by bare land and grass, influenced by the activities of organisms and soil structure.
- All of shrubs and vegetation have the average height about 1(m) - 1.5(m) and they have the cover alternative are 50(%) - 70(%).All of them are good growth under the canopy of indigenous species
1.5 The comments about the condition and competitive relationships among species in the research areas
In Plot 1, various species coexist in the canopy of Pinus massoniana, with a focus on two dominant and competitive species: Pinus massoniana and Erythrophleum fordii The density of Pinus massoniana is approximately 240 trees per hectare, while Erythrophleum fordii has a density of around 200 trees per hectare, indicating significant competition between the two species Pinus massoniana averages a height of 15.2 meters, surpassing Erythrophleum fordii's average height of 13.9 meters; however, this does not necessarily imply stronger growth Despite larger timber sizes, the crown-canopy of these species is smaller compared to indigenous species, and both exhibit slow growth rates Erythrophleum fordii is particularly noted for its shade tolerance.
In the research area of plot 1, Pinus massoniana serves as a favorable environment for the growth of 21 tolerant species, comprising 40.6% of the total tree population with 24 individuals, most of which have small canopies and few instances of mortality Additionally, Erythrophleum fordii, representing about 34% of the total trees with 20 individuals, exhibits robust growth, large canopies, and is free from pests.
Plot 2 exhibits a greater diversity of species compared to Plot 1, featuring numerous mature Pinus massoniana trees, which have high canopies and large trunks but relatively small crowns Similarly, in Plot 1, Erythrophleum fordii thrives beneath the Pinus massoniana canopy, benefiting from favorable conditions that promote its robust growth and larger canopy However, this competition for nutrients and water poses significant challenges for the regeneration of Pinus massoniana, as saplings struggle to obtain adequate light and nutrients necessary for their development.
In plot 3, there are 17 individuals of Erythrophleum fordii and 19 individuals of Pinus massoniana, along with 13 individuals of other species Similar to plots 1 and 2, Pinus massoniana exhibits robust trunk growth, although its canopy remains small Species that thrive beneath the canopy of Pinus massoniana demonstrate enhanced growth due to adaptation and competition.
DISCUSSION
Based on the assessment of the structure, growth, and regeneration of species in the research areas, I recommend implementing specific silvicultural practices in the experimental forest These practices aim to balance forest growth, particularly by pinching timber trees to promote the regeneration of saplings.
The ongoing competition between indigenous plant species and timber tree species in the experimental forest is affecting the forest's species composition The intense rivalry for resources such as space and nutrients is leading to a gradual shift in the forest ecosystem Without intervention to manage nutrient distribution and space for timber trees, indigenous species with longer growth periods may proliferate, resulting in insufficient nutrition and poor living conditions for timber trees This could ultimately lead to reduced growth rates and increased mortality among these timber species.
The following are some of my comments about the situation and some technical measures for the species composition of the experimental forest areas was studied:
In the Luot mountain region, the predominant timber species is Pinus massoniana, with Acacia auriculiformis being less significant This research focuses on evaluating the experimental forest, highlighting the need to manage the density of indigenous species like Erythrophleum fordii to ensure sufficient nutrients for the timber trees It is essential to approach canopy opening strategically, as excessive removal can disrupt and damage the forest structure.
The density of timber trees, specifically Pinus massoniana, ranges from 190 to 240 trees per hectare, while the indigenous species Erythrophleum fordii exhibits densities between 160 and 200 trees per hectare Understanding these density variations is crucial for effective forest management and conservation strategies.
To manage tree density effectively, it is essential to promote the growth of two specific species through natural regeneration and additional planting in areas with low tree density Concurrently, thinning low-quality trees in high-density regions will create more space and nutrients, allowing the remaining species to thrive.
We can conduct the technical measures as follows:
Thinning is essential for enhancing tree growth by removing twigs, branches, and even entire trees from the canopy layer, thereby improving nutrient access and space for remaining species To effectively implement thinning, it is crucial to prepare construction design documents, mark the trees, and follow a structured implementation process Additionally, testing various succession models of timber trees alongside indigenous species can promote the development of mixed forests, with a focus on timber tree species as the primary component.
- To take care of the timber tree: to break down shrubs, liana may affect to the growth of the timber tree, each year to care for 1-2 times
Based on the assessment of the growth and regeneration of the high canopy layer, particularly the Pinus massoniana species, several silvicultural practices are recommended to enhance regeneration In the research areas, saplings are scarce, with most only reaching heights of 10 to 100 cm The poor regeneration of Pinus massoniana can be attributed to the extensive canopy of Erythrophleum fordii, which limits light and nutrients for young saplings Additionally, these saplings are often weakened by competition from surrounding shrubs and vegetation, leading to high mortality rates among young trees In contrast, indigenous species exhibit greater regeneration capacity as they are adapted to shaded environments To improve the density and regeneration of timber trees, it is essential to implement silvicultural practices that reduce the density and canopy cover of competing vegetation, such as thinning and removal, thereby creating favorable conditions for sapling growth.
CONCLUSIONS 24 REFERENCES
The current situation of species growth in the experimental forest of Luot Mountain is complex, particularly due to the robust growth of indigenous species like Erythrophleum fordii, which negatively impacts other species such as Pinus massoniana This competition has resulted in slow growth rates and low regeneration capacity for Pinus massoniana, undermining the original goal of establishing a mixed forest to enhance productivity and sustainability To address these challenges, it is essential to implement silvicultural measures that mitigate the effects of dominant indigenous species and promote the growth of high-yield timber species Research conducted in areas with specific characteristics has led to the development of silvicultural practices aimed at resolving these issues, ultimately improving forest cultivation and development.
Duong Quang Trung, 2013 “Assessment the status and proposed silviculture measures to conservation Madhuca pasquieri forest in TamQuy natural forest conservation areas, Ha Trung, Thanh Hoa”.pp.16-35
In 2013, Le Dac Thang conducted a study assessing the growth potential of various indigenous understory species within Pinus massoniana forests The research aimed to establish a foundation for transforming pure Pinus massoniana forests into mixed forests in Luc Ngan, Bac Giang.
In her 2010 study, Nguyen Thi Xuan Lien assesses the growth potential of five indigenous understory species of Pinus massoniana, aiming to establish a foundation for transforming pure Pinus massoniana forests into mixed forests in Chi Lang, Lang Son This research, published by Thai Nguyen University, spans pages 36 to 69 and contributes valuable insights for forest management and biodiversity enhancement.
In the 1987 publication by R L Ernst, titled "Growth and yield following thinning in mixed species Allegheny hardwood stands," the author discusses the impacts of thinning on growth and yield in northern hardwood forests This work, edited by R D Nyland and presented at a silviculture symposium in Syracuse, NY, provides valuable insights for forest management practices The findings are documented in Miscellaneous Publication No 13 from the S.U.N.Y College of Environmental Science and Forestry, spanning pages 211 to 222.
Marquis, D A.; Ernst, R L, 1991 “The effects of stand structure after thinning on the growth of an Allegheny hardwood stand” Forest Science 37: 1 182-1 200
Miller and Baumgras (1994) discuss effective silviculture practices aimed at enhancing the management of eastern hardwood forests Their insights are presented in the proceedings of the 22nd Annual Hardwood Symposium, highlighting opportunities for the hardwood industry to tackle environmental challenges The publication emphasizes sustainable methods that can be adopted to improve forest health and productivity while addressing ecological concerns.
SNEDECOR, G W (4th edition) 1946 “Statistical Methods Applied to Experiments in
Agriculture and Biology” Collegiate Press, Inc., Ames, Iowa, U S A
- Some information of species on the research areas
Table 1.7: The data of species on Plot 1
Table 1.8: The data of species on Plot 2
Table 1.9: The data of species on Plot 3
No NAME D1.3(cm) Crown-canopy(m) H(m) Note