Teak ( Tectona grandis Linn. f) and Edaphic Factors Affecting the Regeneration of Woody Species and Their Functional Traits in Economic Forest Plantation, Northern Thailand

Improved understanding of relationships among plant traits, stand characteristics, and soil properties can provide insights into the regenerating tree communities of commercial teak plantations. We investigated whether plant traits could be used to predict the natural regeneration of woody species in teak plantations with diferent soil and stand conditions. Data were collected in ffty 20 m × 20m plots that were established in teak plantations of varying ages in northern Tailand. We analyzed diferences in stand characteristics, soil properties, and community-level functional traits among sites. Te RLQ analysis was performed to explore the associations among species abundances, plant traits, and a combined set of soil variables and stand characteristics. Our results showed that tree species with high leaf dry matter contents and high wood density dominated communities in an older teak plantation and were associated with high OM and N concentrations. Trees with larger leaves are increased in plantations that had experienced their frst teak thinning, and were rich in organic matter. Species with high specifc leaf areas increased in sites with high teak basal areas and which had experienced more intense thinning on fertile soils. Tick-leaved species had high importance values on sites with high densities of teak and infertile soils. Our results indicated that tree communities with similar conspecifc traits were associated with specifc soil and stand conditions in teak plantations. A knowledge of these regeneration dynamics may allow forest managers to encourage increased natural regeneration and enhanced diversity in commercial teak plantations.


Introduction
Forest plantations are intensively managed planted forests that are composed of one or more species at maturity.Plantations are characterized by controlled age structure and intertree spacing during the processes of aforestation or reforestation [1].Tey provide goods and services that include timber, nontimber forest products, watershed protection, air purifcation, erosion control, biodiversity, aesthetic value, carbon sequestration, and climate control [2].A large proportion of global wood products are sourced from plantation forests [3].Industrial plantations are often established on degraded lands, which represent an opportunity for restoring forest landscapes and reducing threats to natural systems [4,5].However, commercial plantations are usually planted in monocultures that are expected to have lasting efects on forest structure, diversity, and functioning [6].Terefore, promoting the natural regeneration of other native plants in plantations could enhance plant diversity and promote forest structures and functions that are closer to those of the natural forests [7][8][9].
Teak (Tectona grandis Linn f.) is an important plantation species that has gained worldwide prominence due to the durability and attractive appearance of its wood.Teak is one of the most valuable timber species in the tropics and is grown on over 2.25 million ha globally [10].Teak is native to India, Myanmar, Tailand, and Laos and was translocated to parts of Africa and Central and South America during the past century [11].In Tailand, teak grows in natural forests throughout the northern part of the country.Te suitable natural habitats of them are most positively signifcant with elevation and soil variable [12,13].Teak is a dominant species in the mixed deciduous forest (MDF); however, it can be absent from the MDF [14,15] and the other codominant species such as Pterocarpus macrocarpus, Xylia xylocarpa, Afzelia xylocarpa, and Dalbergia oliveri, and deciduous bamboos can be associated [16].
Te Tai government has pursued a policy of intensive teak logging in these natural forests, resulting in the depletion of teak throughout the northern part of Tailand [17].Currently, the Tai government is promoting the establishment of teak plantations to support the country's wood demand, foster watershed improvement, and restore degraded forest reserves [18].Te Forest Industry Organization (FIO) is the state enterprise that operates planted commercial plantations to produce timber, and it manages teak, eucalyptus, and para rubber across 245 plantation sites.Teak plantations occupy the largest proportion of this area and cover 79,680 ha, especially in northern Tailand.Tese plantations are managed using principles of sustainable commercial forest plantation management to promote both environmental and socioeconomic sustainability [19].Terefore, there is an urgent need to promote the diversifcation of plant communities in FIO plantations to comply with Tailand's environmental sustainability policy.
Previous studies have suggested that promoting the natural regeneration of native species in teak plantations is a key step to increasing their plant diversity [20][21][22].Soil properties and plantation characteristics are important factors that infuence plant regeneration in teak plantations.Soil nutrient concentrations, organic matter, and other chemical and physical properties of soils in teak plantations tend to promote high soil fertility [23].Teak plantations may increase soil fertility relative to the soil conditions that prevail in disturbed forests [24].Relative soil fertility can infuence woody species richness in teak plantations [25].Plantation density, canopy cover, and age all afect plant regeneration in teak plantations.For example, densely planted teak plantations reduce colonization by other native plants because closed canopies efectively shade out and inhibit the natural regeneration of woody species [22,26,27].
Plant functional traits can potentially be used to develop predictive frameworks for the community assembly of natural regeneration in plantations [28][29][30].Plant functional traits are morphological and physiological characteristics that afect plant performance by infuencing survival, growth, and reproduction.Traits represent biological adaptations to local environments that determine ecological strategies for reproduction and resource capture [31,32].Recently, the relationships between plants and soils have been used to create trait-based frameworks for examining plant community establishment [33][34][35].Tus, a better understanding of the relationships among plant traits, soil properties, and conditions in teak plantations should improve researchers' ability to predict the regeneration characteristics that are likely to be successful in these environments.
In this study, we investigated the natural regeneration of woody species in teak plantations, paying special attention to the associations between plant functional traits, soil variables, and plantation characteristics.Specifcally, we addressed two questions.First, can the functional traits of woody species be used to predict the successful establishment of natural regeneration in teak plantations?Second, how do diferent soil conditions and teak plantation characteristics infuence the plant functional traits that promote successful regeneration?Te results of this study may contribute to the development of trait-based management frameworks and improve predictions of woody species regeneration in teak plantations.
Te commercial teak plantation was established in Khun Mae Khum Mee by dividing the area into 17 planting plots.Te frst plantation plots were established in 1968.Successive episodes of logging and replanting resulted in 36 subplots with tree ages that vary from 1 to 40 years.All plantation plots were planted with teak at a spacing of 4 m × 4 m (625 trees per ha).Pruning and weeding were performed annually for the frst fve years using hand tools.Te frst thinning was performed after 15-year-old by cutting 50% of the stems, yielding a residual tree density of 312 trees per ha.A second 50% thinning took place at 25-year-old, resulting in a residual density of 156 trees per ha.Te fnal harvest mostly took place after 30-year-old, but some plots were left until 40-year-old to produce large-dimension timber.Some oldgrowth forests that stand in the area are the secondary MDFs that remained in the area after government-sponsored logging.Tey cover approximately 20% of the plantation area and are currently protected [36].

Sampling Plot Selection and Tree Data Collection.
We collected data from January to December 2020.Sampling was conducted in 10-, 20-, 30-, and 40-year-old plots and in oldgrowth forests.All sites had similar topographic and geographic settings (elevation 400-450 m asl and slope approximately 40-45%) (Table 1).Within each site, we established ten 20 m × 20 m (0.04 ha) plots for a total of 50 plots (2 ha).Diameter at breast height (DBH, cm) and height (m) of all mature trees ≥1.3 m tall and ≥4.5 cm DBH were measured in each 0.04 ha plot.All trees were identifed to the species level by comparing collected specimens with identifed specimens in 2 International Journal of Forestry Research the Forest Herbarium (BKF), Department of National Parks, Wildlife and Plant Conservation.Te nomenclature used in this study followed the system used by Pooma and Suddee [37].

Soil Measurements.
In each 20 m × 20 m sampling plot, we sampled soil variables that included soil texture (percent sand, silt, and clay), pH, organic matter (OM, %), and soil nutrients, including N (%), P (mg kg −1 ), K (mg kg −1 ), Ca (mg kg −1 ), and Mg (mg kg −1 ).Soil samples were collected as 100 cm 3 soil cores extracted from the topsoil layer (0-15 cm) in October 2020.To calculate the mean value of soil properties in each 20 m × 20 m plot, fve cores were taken from the center and each of the four corners of the 0.04 ha plots.Tese soil samples were used to analyze the soil texture, pH, OM, and available N, P, K, Ca, and Mg at the soil laboratory of the Faculty of Forestry, Kasetsart University.

Functional Trait Measurements.
Five functional traits of mature trees were chosen for analysis: specifc leaf area (SLA, cm 2 g −1 ), leaf dry matter content (LDMC, mg g −1 ), leaf area (LA, cm 2 ), leaf thickness (LT, mm), and wood density (WD, g cm −3 ).Tese traits are associated with plant ecological strategies that are related to competitive ability,  International Journal of Forestry Research growth potential, and physical resistance to damage [32].Fifty-six species of mature trees represented by ≥3 individuals in all 50 plots were selected for the measurement of trait data (Table 2).In this study, teak trait data were not collected.Te traits in question were measured in three individuals from each species and the mean values for each trait were calculated.In October 2020, we sampled 3-10 sun leaves from each individual to calculate the mean values of SLA, LDMC, LA, and LT.Fresh leaves were scanned using ImageJ software (https://rsbweb.nih.gov/ij/ ), and LA was calculated from these leaf images.Leaf mass was measured from fresh leaves, and leaf dry mass was measured after samples had been oven-dried at 60 °C for 48 h.Specifc leaf area was calculated as the ratio of fresh LA divided by oven-dried mass, and LDMC was calculated as the ratio of oven-dried to fresh leaf mass.We determined LT from the mean leaf blade thickness from fve leaf samples, measured using a thickness gauge (China YH-1; Zhejiang, China).Wood samples for WD determination were collected at breast height (1.3 m) using 5 mm increment borers, after which they were oven-dried at 70 °C for 48 h.Wood density was then calculated as the ratio of oven-dried to fresh wood volume.

Data Analyses.
For each site, we calculated mean values of DBH, stem density (stem ha −1 ), stem basal area (BA; m 2 ha −1 ), and height.Similarly, mean values of all soil properties were calculated for each site.One-way analysis of variance (ANOVA, critical p < 0.05) was used to test for statistically signifcant diferences among functional traits and soil variables.We used stem density, basal area, relative stem density, and relative basal area to perform species composition analysis.From these data, we calculated the importance value index (IVI) to identify the dominant species at each site.An IVI value is calculated as the sum of relative stem densities and relative basal areas for each site [38].In addition, we calculated the Shannon-Wiener index as a measure of tree species diversity in each site [39].
To characterize trait dominance, the community-level weighted mean (CWM) of each trait was calculated at each site, as follows: where p i and tr i are the relative abundance and trait value of species i and n is the total number of species per plot.Values of CWM were calculated using the FD package [40] in the R statistical environment.One-way ANOVAs were used to characterize and quantify diferences in mean CWMs for SLA, LDMC, LA, LT, and WD at each site.
We used RLQ analysis and the fourth corner method to explore the association of species composition, plant traits, and environmental variables.RLQ analysis uses multivariate ordination techniques to explore the intercorrelations of species abundance (matrix L), species traits (matrix Q), and environmental variables (matrix R) [41].Matrix R comprised soil pH, the percentages of sand, silt, and clay, OM, N, P, K, Ca, and Mg, together with teak stem density (stem ha −1 , TD), teak basal area (m 2 ha −1 , TBA), time since thinning (Tin), and plantation age.A Monte Carlo permutation test was performed with 999 permutations to assess the statistical signifcance of each environmental variable using the vegan package for R. Fourth corner analysis represents the correlation between plant traits and environmental variables when assessed using species relative abundance [42].To assess individual species trait-environment relationships, we used the fourth corner to jointly perform a permutation test on the combined model 2 (permutation values of sites) and model 4 (permuted values of species) outputs (n = 49,999 permutations).RLQ and fourth corner analyses used the ade4 package [41] for R.

Teak Characteristics.
Mean values of DBH, basal area, stem density, and height of the teak varied signifcantly among sites (Table 3).Te largest DBH trees (mean � 24.91 cm) were found in 40-year-old teak sites, followed by those in sites that were 30, 20, and 10 years old (p < 0.001).Old-growth forest sites had the smallest teak stems.Basal area was also larger in 40-year-old teak sites (10.85 m 2 ha −1 ), followed by the 20-, 10-, and 30-year-old sites and old-growth forest (p < 0.001).Similarly, the tallest teak grew in the 40-year-old sites (mean height � 23.85 m), followed by 20-, 30-, and 10-year-old sites and the oldgrowth forest (p < 0.001, Table 3).Maximum stem density occurred in the 10-year-old sites (478 stems ha −1 ), followed by 20-, 40-, and 30-year-old sites and old-growth forest, respectively (p < 0.001).Te dimensional traits of teak were at their smallest on old-growth forest sites because most teak on these sites were stump sprouts that grew after logging had occurred.

Soil Properties.
Several soil properties difered among sites (Table 4).Te percent sand was signifcantly greater in 10-year-old and old-growth forest sites (p < 0.001).Percent clay was higher in 40-and 20-year-old sites than elsewhere (p < 0.001).Forty-year-old sites had a greater pH and higher concentrations of OM, N, Ca, and Mg than other sites, but the concentration of soil K was highest in old-growth forests (all p < 0.001).Percent silt and P concentrations were similar across sites (Table 4).

Woody Species Composition.
Ten-year-old teak sites had the highest stem densities but the lowest basal area values (Table 5), suggesting that these sites supported large numbers of small stems.Twenty-year-old sites had the lowest species richness (21 species), species diversity (Shannon-Wiener index � 1.56), and stem densities (mean � 570 stems ha −1 ).By contrast, 30-year-old sites supported the most species (47 species) and had the highest Shannon-Wiener diversity index (2.75), a value similar to that in old-growth forest sites (2.72).Te BA of 40-year-old sites was greater than those of other sites.Both the BA and stem density of this age class were similar to values recorded at old-growth forest sites (Table 5).
Te fve dominant species ranked according to IVI are shown in Table 6.Planted teak dominated plantation sites at all ages but ranked ffth among woody species in old-growth forest sites due to their production of small postlogging stump sprouts.Pterocarpus macrocarpus was the dominant species in old-growth forests and the second most dominant species in 10-, 30-, and 40-year-old sites.Xylia xylocarpa was also dominant in old-growth forest sites and in 10-, 20-, and 30-year-old sites.Albizia odoratissima was the third most dominant species in old-growth forest sites and in 20year-old sites and was the fourth most dominant species in 40-year-old sites.Dalbergia cultrata was the ffth most dominant species in 10-and 20-year-old sites.Species whose IVI values were ranked in the top fve in only one age class were Aporosa nigricans, Dalbergia nigrescens, Terminalia mucronata, Schleichera oleosa, Vitex canescens, and Croton persimilis (Table 6).

Functional Trait Dominance.
At the community level, CWM values of LT, LA, SLA, LDMC, and WD varied signifcantly among sites (Table 7).CWM values of LT were signifcantly higher in 10-and 20-year-old sites than in others.Similarly, the CWM of LA was highest in 20-year-old sites followed by 10-year-old sites.Te CWM values of SLA and WD were signifcantly larger in 40-and 30-year-old sites and old-growth forest sites than in other age classes.Oldgrowth forest sites also had a signifcantly higher CWM of LDMC than any of the plantation-age classes (Table 7).

Relationships among Species Abundance, Functional
Traits, and Soil Variables.Te RLQ analysis revealed signifcant relationships among dominant species, plant traits, and local environmental variables.Fourth corner analysis indicated that the soil variables combined with teak stand characteristics were signifcantly correlated with all of the tree traits when assessed using species relative abundance (p < 0.001 for model 2, p < 0.05 for model 4; fourth corner test).Te RLQ eigenvalues were 1.124 and 0.074 for axes 1 and 2, respectively.Tese axes captured 93% of the covariance in species abundances (L matrix), trait values (Q matrix), and environmental variables (R matrix) (Figure 2).Species characterized by high LDMC, large leaves, and dense wood, such as Fernandoa adenophylla (FERAD), Albizia odoratissima (ALBOD), Xylia xylocarpa (XYLXY), Cassia fstula (CASFI), and Schleichera oleosa (SCHOL), colonized old growth stands.Tese species were associated with soils containing greater proportions of silt and clay, as well as higher organic matter (OM) and N contents.Species with high SLA, such as Dalbergia oliveri (DALOL), Phanera bracteata (PHABR), Pterocarpus macrocarpus (PTEMA), Terminalia nigrovenulosa (TERNI), and Dalbergia nigrescens (DALNI) were abundant in teak plantations with higher BA in which more time had elapsed since thinning.Tese species were also associated with higher pH, Mg, Ca, P, and K. Ticker leaved species such as Artocarpus lacucha (ARTLA), Canarium subulatum (CANSU), Dolichandrone serrulata (DOLSE), Terminalia bellirica (TERBE), and Lagerstroemia macrocarpa (LAGMA) were abundant in dense teak plantations and were also associated with higher percent sand and lower concentrations of soil nutrients (Figure 2).

Discussion
Our results indicated that the relative abundance and conspecifc functional traits of regenerating tree communities change in response to soil conditions and the 6 International Journal of Forestry Research   International Journal of Forestry Research characteristics of teak plantations, as conditioned by forest harvesting practices.Te RLQ and fourth corner analysis indicated that relationships between plant functional traits and the environment (soil variables and teak stand characteristics) could be explained by woody species composition at these sites.We found that tree community composition is driven by the dominant tree species.Tus, the plant functional traits of dominant species are modulated by soil conditions combined with teak plantation characteristics, and this feedback appears benefcial in the context of teak plantations.Te woody species associated with higher values of LDMC, dense wood, and larger leaves were positively associated with older teak plantations and soils with higher percent clay and elevated OM and N.At the community level, the CWM of LDMC reached its highest value in the old-growth forests, while the CWM of WD was higher in 40year-old teak sites and old-growth forests.Tese older sites were associated with higher concentrations of OM and N. Trees with high LDMC and denser wood are often slowgrowing, late-successional species associated with climax communities of tropical forests [44][45][46].High wood density is associated with low volumetric stem growth rates, resistance to damage, high rates of survival, and resistance to drought [47,48].LDMC is a proxy for mass investment in photosynthetic organs that is negatively correlated with plant growth.Species associated with high values of LDMC usually display slow growth rates, low nutrient concentrations, and low rates of leaf turnover [49][50][51].Tese fndings indicate that stand conditions in teak plantations abandoned ten years after the second thinning (i.e., 30-year-old plantations) can encourage colonization by late-successional species.
We also found that large-leaved trees tended to dominate 20-year-old teak plantations with high values of OM.Largeleaved species are associated with soil nutrient stresses and high disturbance rates [32].Leaf area determines lightinterception capacity and is well suited for highthroughput screening of plants because LA measurements can be performed nondestructively and economically [52,53].In 20-year-old teak plantations abandoned for fve years after a 50% thinning, the large gap sizes left by harvesting encouraged colonization by large-leaved species.However, dominant trees characterized by large leaves, high LDMC, and dense wood did not readily establish in 20-and 40-year-old plantations or old-growth forest areas.Tese sites tended to have high levels of OM and soil N due to leaf litter accumulation and decomposition.Leaf litter decomposition and the consequent accumulations of OM and N are crucial components of ecosystem functioning in forest soils [54,55].Organic matter maintains soil structure, especially in fne-textured soil [56].Nitrogen is one of the most essential elements for plant growth and development [57].In our study, it appears that high OM and soil N concentrations promoted colonization and survival of late-successional or climax species in the 40-year-old plantation and old-growth forest.
Tree species with high SLA were positively associated with high TBA and greater time since thinning.Tese species were positively associated with higher pH values and    2. Abbreviations of soil variables and traits are provided in Tables 4 and 7, respectively.
International Journal of Forestry Research high concentrations of Mg, Ca, P, and K.At the community level, species with high values of SLA were important components of 30-and 40-year-old plantations and oldgrowth forests.Specifc leaf area is thought of as an acquisitive trait, which encourages a fast recovery of foliar investment and fast turnover of matter and energy.It is therefore linked to fast growth and high photosynthetic rates [58,59].Specifc leaf area is a proxy for the leaf economic spectrum that plays an important role in determining plant productivity via high rates of photosynthesis and the accumulation of starch and sugars [60,61].Lohbeck et al. [45] reported that in dry tropical forests, SLA at the community level decreased with increasing BA during succession.Tis result contrasts with our fnding that high-SLA species dominated the 40-year-old plantation, which had a high TBa.Tese results suggest that the larger size of teak in older plantations could have inhibited successional processes.Tese fndings confrm that SLA is an important trait for predicting the outcomes of secondary succession in natural forests and plantations and may be used to predict successional patterns across diferent vegetation types [47].High-SLA species were positively associated with greater time since thinning, suggesting that high-SLA species could become increasingly important in successional communities as abandoned plantations age.Dwyer and Mason [62] reported that thinning led to an overabundance of high-SLA species, akin to pioneer dominance during the early stages of rainforest succession.Tinning has been applied to ecological restoration and is thought to be particularly efective at accelerating plant community recovery in some forests that were dominated by a single species [62,63].Te timing of thinning has a greater infuence on plant regeneration than thinning intensity [64].Te greater time since the thinning of teak in 30-and 40-year-old teak plantations changed microenvironmental conditions by increasing light levels in open canopy gaps, which improves conditions for the regeneration of fast-growing species with high SLA.
High-SLA species that also had high IVI were associated with fertile soils in the 30-and 40-year-old sites and in the old-growth forest sites.Tis relationship indicated a plant response to soil nutrients that may refect a nutrient-related trade-of between plant regeneration and SLA.Tis fnding is supported by previous studies showing that plant communities dominated by high-SLA species are usually found in habitats with good soil nutrient supply and are characterized by rapid nutrient uptake [61,62,65].Terefore, the timing of thinning treatments and fertile soil appear to have promoted the colonization and persistence of high-SLA species.
Te CWM data showed that thick-leaved species achieved their greatest dominance in 10-year-old teak plantations with high densities of teak and sandy soils.Leaf thickness is a plant trait related to variations in sunlight and shade.Plant communities with thick-leaved species may also dominate dry, sunny habitats [32,66].Te internal leaf structure of thick leaves may feature high stomatal densities and lower chlorophyll contents.Tick leaves are also expensive to construct and are associated with long leaf lifespans [66,67].Tick sun-grown leaves are associated with high water-use efciency, where productivity is maintained without increased water use [68].Leaf thickness is a conservative functional trait with a generally slow return on investment [58].
Although the 10-year-old sites showed high teak stem densities, these stems were short and had narrow canopies, allowing intense sunlight to reach the ground.Tese forest conditions may have favored the establishment of thick-leaved species.Lohbeck et al. [45] report that LT at the community level increases with dry forest succession in the tropics.Tick-leaved species were associated with sandy, nutrient-poor soils, which were also a feature of the 10-year-old sites.Sandy soils in the tropics are often infertile because of their high sand content, low waterholding capacity, low cation exchange capacity, and low plant-available nutrients [69].Previous studies suggest that species with high LT are drought-tolerant in droughtprone and nutrient-poor soils, and thick leaves may enhance nutrient-use efciency in these stressful environments [34,35].In accordance with these previous fndings, thick-leaved species in our study preferentially colonized the intensely irradiated and nutrient-poor 10year-old sites.

Conclusion
In this study, we investigated whether functional traits of woody species could be used to predict the composition of natural regeneration in teak plantations with diferent soil conditions and site characteristics (stem density, basal area, age, and time since thinning).We found that the 10-year-old teak plantation had the highest teak stem density but the smallest stems.Tis plantation was also established on sandy, nutrient-poor soils, and conditions that promoted the regeneration of woody species with thicker leaves.A 20-year-old teak plantation was highly disturbed after its frst thinning at 15-year-old.Tis plantation was associated with high OM but lower nutrient concentrations, conditions that encouraged the regeneration of larger-leaved species.More time had elapsed since thinning in the 30-and 40-year-old plantations, and these sites were associated with fertile soils with high concentrations of Mg, Ca, P, and K. Tese conditions appear to have enhanced the regeneration of woody species with high SLA.Te old-growth forest and 40-year-old teak plantation (both of which had experienced a longer period of abandonment) were associated with fertile soils, which appear to have promoted the regeneration of woody species with high LDMC and high WD.Tese results show that the impacts of teak plantation characteristics and soil conditions modify the balance of tree functional traits in regenerating communities of native tree species.Tus, future management interventions for enhancing tree diversity and abundance in teak plantations should consider the plant traits that are associated with a given combination of soil conditions and stand characteristics.By doing so, forest managers may successfully manage the biodiversity of regenerating trees in commercial plantations.10 International Journal of Forestry Research

Figure 1 :
Figure 1: Location of sampling plots and the Khun Mae Khum Mee plantation in Phrae province, northern Tailand.

Figure 2 :
Figure 2: Results of RLQ analysis for axes 1 and 2 showing relationships among (a) dominant species, (b) soil variables and teak stand characteristics, and (c) plant traits.Te value of d indicates grid size.Species codes are provided in Table2.Abbreviations of soil variables and traits are provided in Tables4 and 7, respectively.

Table 1 :
Description and silvicultural practice of sampling sites of teak plantation plots on 10-, 20-, 30-, and 40-year-old and old-growth forest sites in Khun Mae Khum Mee plantation, Phrae province.

Table 2 :
[43]y species, species codes, and numbers of stems present in the ffty 0.04 ha plots.International Journal of Forestry ResearchTeak data were excluded from the species and trait matrices in CWM and RLQ because teak stand variables formed part of the environmental matrix.Te CWM and RLQ were analyzed in R software (version 4.2.2)[43].

Table 5 :
Ecological characteristics of teak plantation and old-growth forest plots in Khun Mae Khum Mee plantation.

Table 6 :
Te fve dominant species in teak plantation and old-growth forest plots in Khun Mae Khum Mee plantation.