Developing relative stand density index for structurally complex mixed species cypress and pine forests

Yang, Ting-Ru; Lam, Tzeng Yih; Kershaw, John A.

doi:10.1016/j.foreco.2017.11.043

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…Likewise, the logarithmic regressions fitted to the volume-density ceiling spotted values, probably do not represent the real self-thinning lines of different land-use systems as in Portuguese cork oak woodlands (Fonseca et al 2017). Yet, as shown by Condés et al (2017) and Yang et al (2018), it assumes that the fitted regression lines in the present study are either parallel to corresponding lines formed by quantile regressions, or parallel to lines passing through ceiling points resulted from a large number of intermediate plots or allometric models (Pretzsch 2009). Thus, we conclude that, although the coppicing is the major stress on these woodlands, the Brant's oak woodlands, even in the presence of extensive grazing, can cope the cutting stress significantly better than when they are under pressure of understory rain-fed cultivation.…”

Section: Discussionmentioning

confidence: 94%

Effects of different land-use systems (grazing and understory cultivation) on growth and yield of semi-arid oak coppices

2019

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high level of agreement with self-thinning rule of − 3/2. Values for the stand density index for coppiced oak woodlands were between more than 1000 for the least disturbed (Co) and less than 400 for the most disturbed woodlands (CoCG). The structure and growth rate of the coppiced oak woodlands were irreversibly disrupted by understory tillage plus grazing and in less extent by grazing alone. It was concluded that ending undergrowth cultivation in semi-arid oak coppices should be addressed as a priority by adopting minimum regulations.

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Section: Discussionmentioning

confidence: 94%

Effects of different land-use systems (grazing and understory cultivation) on growth and yield of semi-arid oak coppices

2019

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“…In Taiwan, forests occupy about 60% of the total land area of about 36,200 km 2 , which could be grouped into five general types: broadleaf forest, coniferous forest, mixed broadleaf-coniferous forest, mixed bamboo broadleaf forest, and mixed bamboo coniferous forest 15 , 16 . The 4th Taiwan National Forest Resource Inventory conducted between 2008 and 2012 reported that total carbon storage in Taiwan forests was 754.3 Mt CO 2 or 347.9 t CO 2 ha −1 15 , 17 .…”

Section: Introductionmentioning

confidence: 99%

Modeling biomass allocation strategy of young planted Zelkova serrata trees in Taiwan with component ratio method and seemingly unrelated regressions

Chen

Lam

2021

Sci Rep

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Trees accumulate biomass by sequestrating atmospheric carbon and allocate it to different tree components. A biomass component ratio is the ratio of biomass in a tree component to total tree biomass. Modeling the ratios for Zelkova serrata, an important native reforestation tree species in Taiwan, helps in understanding its biomass allocation strategy to design effective silvicultural treatments. In this study, we applied Component Ratio Method (CRM) to relate biomass component ratios of main stem, large branch, twig, and foliage to tree attributes of Z. serrata from a 9-year-old plantation. Nonlinear and linear CRM models were fitted with Seemingly Unrelated Regression to account for model correlations. Linear CRM models with dbh as the predictor had the best fit with model correlations as high as 80%. About 46% and 40% of total tree biomass was allocated to main stem and large branch, respectively. However, main stem biomass decreased by 1.9% with every 1-cm increase in dbh, but large branch biomass increased by 2.2% instead. Results suggest that dominant Z. serrata trees tend to branch and fork, while smaller trees invest in larger main stem. An early pruning treatment should focus on dominant trees to maintain crown ratio and ensure wood quality.

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“…Selective thinning through human intervention is a vital management measure for adjusting forest density and, as such, it has been widely implemented in forestry production [1][2][3][4][5]. It can directly or indirectly influence changes in the microclimatic conditions of forest stands, such as light levels, temperature, and water content [6][7][8], as well as the stocks and dynamics of soil organic carbon [9].…”

Section: Introductionmentioning

confidence: 99%

Effects of Thinning on Microbial Community Structure in the Organic Horizon of Chinese Pine Plantations in Badaling, Beijing, China

GuangLiang¹,

Sun

Yang

et al. 2019

Forests

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Research Highlights: Moderate thinning can effectively improve forestry production and change the microenvironment of understory vegetation. Background and Objectives: Microbial communities control the decomposition and transformation of forest organic matter; however, the influence of thinning on microbes in the organic horizon remains unclear. Materials and Methods: In this study, we subjected four plots of Chinese pine plantations in Badaling, Beijing to different thinning intensities, including no thinning (T0), low-intensity thinning (T10), medium-intensity thinning (T20), and high-intensity thinning (T50). The changes in chemical properties and microbial community compositions observed in the organic horizon, which comprised undecomposed litter (L layer) and half-decomposed litter (F layer), were analyzed after thinning. Microbial community compositions were evaluated using phospholipid fatty acid (PLFA) methods. Results: The results showed that the abundances of gram-negative bacteria (GN) and total bacteria (B) under the T10 thinning condition were the highest among the four thinning intensities, and the abundance of arbuscular mycorrhizal fungi (AMF) in T20 was higher than under other thinning intensities. The abundance of gram-positive bacteria (GP) and actinobacteria (ACT) in T10 was lower than in both T0 and T50. The abundance of total PLFAs and fungi (FU) was higher in the L layer, whereas the abundance of GP, GN, B, ACT, and AMF was higher in the F layer. Conclusions: Our results demonstrated that the L layer better reflects the influence of thinning on litter. Redundancy analysis (RDA) results indicated that the organic carbon (LOC) , dissolved organic carbon (DOC), and ammonium nitrogen (NH4+-N)contents of litter were primarily responsible for the observed changes in microbial community structure, with LOC alone explaining 62.6% of the total variance among the litter substrate factors selected. Overall, moderate-intensity thinning of Pinus tabulaeformis Carr. plantations created more favorable conditions for microbial communities in the organic horizon.

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Developing relative stand density index for structurally complex mixed species cypress and pine forests

Cited by 8 publications

References 19 publications

Effects of different land-use systems (grazing and understory cultivation) on growth and yield of semi-arid oak coppices

Effects of different land-use systems (grazing and understory cultivation) on growth and yield of semi-arid oak coppices

Modeling biomass allocation strategy of young planted Zelkova serrata trees in Taiwan with component ratio method and seemingly unrelated regressions

Effects of Thinning on Microbial Community Structure in the Organic Horizon of Chinese Pine Plantations in Badaling, Beijing, China

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