Evaluation of distance-independent competition indices in predicting tree survival and diameter growth

Sun, Shuang; Cao, Quang V.; Cao, Tianjian

doi:10.1139/cjfr-2018-0344

Cited by 21 publications

(30 citation statements)

References 24 publications

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“…We used six distance-independent competition indices: basal area of trees larger than the subject tree (BAL), diameter ratio (DR), basal area ratio (BR), cumulative distribution function (CDF), relative spacing index (Sr), and SDI according to the definition of Sun et al [11].…”

Section: Distance-independent Competition Indexmentioning

confidence: 99%

“…These models incorporate flexible tree growth processes; thus, this model is robust in predicting tree growth under various conditions [3]. In addition, in contrast to the stand-level model, the individual-level model can predict the volume and other parameters of each diameter class within a stand by summarizing individual-tree estimates [6][7][8][9][10][11].Individual-level models are further classified into distance-dependent and distance-independent models. Tree growth in a stand is restricted by stand age, stand condition, and competition with adjacent trees for light, water, and nutrients.…”

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confidence: 99%

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Evaluation of Individual Distance-Independent Diameter Growth Models for Japanese Cedar (Cryptomeria japonica) Trees under Multiple Thinning Treatments

Fukumoto

Nishizono

Kitahara

et al. 2020

Forests

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Understanding the tree growth process is essential for sustainable forest management. Future yields are affected by various forest management regimes such as thinning; therefore, accurate predictions of tree growth are needed under various thinning intensities. This study compared the accuracy of individual-level distance-independent diameter growth models constructed for different thinning intensities (thinning intensity-dependent multiple models: TDM model) against the model designed to include all thinning intensities (thinning intensity-independent single model: TIS model) to understand how model accuracy is affected by thinning intensity. We used long-term permanent plot data of Japanese cedar (Cryptomeria japonica) stands in Japan, which was gathered from four plots where thinning was conducted at different thinning intensities: (1) intensive (41% and 38% of trees removed at 25 and 37 years old, respectively), (2) moderate (38% and 34%), (3) light (32% and 34%), and (4) no thinning. First, we specified high interpretability distance-independent competition indices, and we compared the model accuracy both in TDM and TIS models. The results show that the relative spacing index was the best competition index both in TDM and TIS models across all thinning intensities, and the differences in the RMSE (Root mean square error) and rRMSE (relative RMSE) in both TDM and TIS models were 0.001–0.01 cm and 0.2–2%, respectively. In the TIS model, rRMSE varied with thinning intensity; the rRMSE was the lowest for moderate thinning intensity (45.8%) and the highest for no thinning (59.4%). In addition, bias values were negative for the TIS model for all thinning intensities. These results suggest that the TIS model could express diameter growth regardless of thinning intensities. However, the rRMSE had varied with thinning intensity and bias had negative values in the TIS model. Therefore, more model improvements are required for accurate predictions of long-term growth of actual Japanese cedar stands.

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Section: Distance-independent Competition Indexmentioning

confidence: 99%

mentioning

confidence: 99%

Evaluation of Individual Distance-Independent Diameter Growth Models for Japanese Cedar (Cryptomeria japonica) Trees under Multiple Thinning Treatments

Fukumoto

Nishizono

Kitahara

et al. 2020

Forests

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“…Forest growth and yield models provide foresters the ability to predict future conditions of the forest. Individual tree models have the highest level of resolution and inherent flexibility to project tree and stand development over time for combinations of species mixtures, stand structures, and management regimes [56,57]. This makes individual tree models the ideal tool for management of multifunctional forests.…”

Section: Evaluation Of Competition Indices In Modelling Individual Treesmentioning

confidence: 99%

“…The question was approached by evaluating the inclusion of six distance-independent competition indices in models that predict tree survival and diameter growth [56]. The competition indices were classified into three families: (1) size ratios, which include diameter ratio and basal area ratio; (2) relative position indices, which include basal area of larger trees (BAL) and tree relative position, based on the cumulative distribution function (CDF); and (3) partitioned density indices, which divide the stand density index and relative density into components for individual trees.…”

Section: Evaluation Of Competition Indices In Modelling Individual Treesmentioning

confidence: 99%

Multifunctionality of Forests: A White Paper on Challenges and Opportunities in China and Germany

Benz

Chen

Dang

et al. 2020

Forests

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Both in Germany and in China, there is strong expertise regarding the different aspects of forest management, as well as forest products management. Nevertheless, forestry in both countries is facing challenges, some of which are regional, but many of which are shared. Therefore, experts from both countries (Technical University of Munich Germany; Northwest A&F University Yangling, China; Forestry Academy of Shaanxi, China; Thünen Institut, Germany; FEDRC GIZ Forest Policy Facility (Forestry Economics Development and Research Center of the Deutsche Gesellschaft für Internationale Zusammenarbeit GmbH), Germany; and Center for Natural Forest Protection in Shaanxi, China) met to share their knowledge and deduce recommendations for future multifunctional forest management for the temperate zone. The workshop, held at the Northwest A&F University in September 2018, included presentations and intensive discussions, as well as a field tour. The results of the workshop that are summarized in this white paper are meant to provide an overview of the multi-faceted nature of the topic for interested scientists and forest practitioners, describe tools that can be used to analyze various aspects of multifunctionality and, in an exemplary fashion, highlight gathered experience from long- and short-term experiments. Included are social demands, economic goals, and scientific baselines. The topics reach from economic evaluations of forest ecosystem services over forest management practices, including afforestation, restoration, and preparations to face climate change, to wood/forest products utilization and participation of local people for poverty reduction. Overall, an optimistic picture emerges, showing that by using adapted forest management practices, which try to embrace the concept of multifunctionality, various use schemes and demands can be integrated at single sites, allowing us to achieve both environmental protection and productive forests, including societal demands, as well as aspects of tradition and national identity.

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“…The BAL index is a commonly used distance-independent competition index in individual-tree growth models (Wykoff 1990). This index is stable, applicable and best suited to reflect competition in pine-oak mixed forests in this region (Sun et al 2019). The calculation of BAL was as follows…”

Section: Mixing Effect On Competition and Facilitationmentioning

confidence: 99%

Mixing effect on stand yield ofPinus tabulaeformisandQuercus liaotungensisis modulated by site quality and stand density in the Loess Plateau, China

Xiaozhou

Zhang

2020

Journal of Plant Interactions

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Interactions between plants are complicated: they can change resource availability, the proportion of resources acquired and the efficiency of resource use. This can eventually lead to changes in stand yield, but the driving mechanisms remain controversial. This study aimed to clarify the effects of mixing on stand yield. We established 120 mixed and pure plots of Chinese pine (Pinus tabulaeformis) and Liaodong oak (Quercus liaotungensis) in the Loess Plateau, China. Based on the inventory data in 2009 and 2016, we compared the differences in yields between mixed and pure stands. Our results indicated that the mixing of pine and oak resulted in over-yielding, but there was no transgressive over-yielding and pure pine stands consistently produced the highest yields. The over-yielding was due to facilitation between pine and oak, especially the improvement of light conditions in the understory, and an increase in the light use-efficiency of young pine and the availability of light to young oak. Mixing did not reduce competition: pine was dominant in interspecific competition and inhibited the growth of oak. The mixing effect was affected by site quality and stand density: improvements in site quality reduced over-yielding, while increases in stand density increased over-yielding.

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Evaluation of distance-independent competition indices in predicting tree survival and diameter growth

Cited by 21 publications

References 24 publications

Evaluation of Individual Distance-Independent Diameter Growth Models for Japanese Cedar (Cryptomeria japonica) Trees under Multiple Thinning Treatments

Evaluation of Individual Distance-Independent Diameter Growth Models for Japanese Cedar (Cryptomeria japonica) Trees under Multiple Thinning Treatments

Multifunctionality of Forests: A White Paper on Challenges and Opportunities in China and Germany

Mixing effect on stand yield ofPinus tabulaeformisandQuercus liaotungensisis modulated by site quality and stand density in the Loess Plateau, China

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