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Forest Ecosystems

2014年第1期共有论文7篇

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论文题目：Editorial- Forest Ecosystems

全部作者： Yin Weilun1, and Klaus v Gadow2,3*

期刊名称：Forest Ecosystems 2014年第1期

论文摘要：[查看全部]

论文摘要：[返回]

下载频数：13　　　　　　　上传时间：2014-07-30 　　　　　　　加入收藏

论文题目：Science writing in the real world

全部作者： Mike Mentis

期刊名称：Forest Ecosystems 2014年第1期

论文摘要：The objective of this contribution is to consider guides to technical writing. Since the professional writes what he does and does what he writes, guides to how you execute the one relate to how you perform the other, so this article is about more than just writing. While there is need for...[查看全部]

论文摘要：The objective of this contribution is to consider guides to technical writing. Since the professional writes what he does and does what he writes, guides to how you execute the one relate to how you perform the other, so this article is about more than just writing. While there is need for idiosyncrasy and individualism, there are some rules. Documents must have an explicit purpose stated at the outset. By their nature, documents in the applied sciences and business address real-world problems, but elsewhere activity may be laissez loire for which the cost-effectiveness in yielding innovations is contestable. A hallmark of written science and technology is that every statement is capable of being tested and capable of being shown to be wrong, and that methods yield repeatable results. Caution should be observed in requiring authoritative referencing for every notion, partly because of the unsatisfying infinite regress in searching for ultimate sources, and partly to avoid squashing innovation. It is not only the content of messages that matters, but reliability too. Probability theory must be built into design to assure that strong inference can be drawn from outcomes. Research, business and infrastructure projects must substitute the frequent optimistic 'everything goes according to plan' (EGAP) with a more realistic 'most likely development' (MLD) and the risks of even that not happening. [返回]

下载频数：13　　　　　　　上传时间：2014-07-30 　　　　　　　加入收藏

论文题目：Stand management optimization - the role of simplifications

全部作者： Timo Pukkala1*, Erkki L?hde2 and Olavi Laiho2

期刊名称：Forest Ecosystems 2014年第1期

论文摘要：Background: Studies on optimal stand management often make simplifications or restrict the choice of treatments. Examples of simplifications are neglecting natural regeneration that appears on a plantation site, omitting advance regeneration in simulations, or restricting thinning treatments to...[查看全部]

论文摘要：Background: Studies on optimal stand management often make simplifications or restrict the choice of treatments. Examples of simplifications are neglecting natural regeneration that appears on a plantation site, omitting advance regeneration in simulations, or restricting thinning treatments to low thinning (thinning from below). Methods: This study analyzed the impacts of simplifications on the optimization results for Fennoscandian boreal forests. Management of pine and spruce plantations was optimized by gradually reducing the number of simplifying assumptions. Results: Forced low thinning, cleaning the plantation from the natural regeneration of mixed species and ignoring advance regeneration all had a major impact on optimization results. High thinning (thinning from above) resulted in higher NPV and longer rotation length than thinning from below. It was profitable to leave a mixed stand in the tending treatment of young plantation. When advance regeneration was taken into account, it was profitable to increase the number of thinnings and postpone final felling. In the optimal management, both pine and spruce plantation was gradually converted into uneven-aged mixture of spruce and birch. Conclusions: The results suggest that, with the current management costs and timber price level, it may be profitable to switch to continuous cover management on medium growing sites of Fennoscandian boreal forests.[返回]

下载频数：14　　　　　　　上传时间：2014-07-30 　　　　　　　加入收藏

论文题目：Height increment of understorey Norway spruces under different tree canopies

全部作者： Olavi Laiho1, Timo Pukkala2* and Erkki L?hde1

期刊名称：Forest Ecosystems 2014年第1期

论文摘要：Background: Stands having advance regeneration of spruce are logical places to start continuous cover forestry(CCF) in fertile and mesic boreal forests. However, the development of advance regeneration is poorly known. Methods: This study used regression analysis to model the height increment of...[查看全部]

论文摘要：Background: Stands having advance regeneration of spruce are logical places to start continuous cover forestry(CCF) in fertile and mesic boreal forests. However, the development of advance regeneration is poorly known. Methods: This study used regression analysis to model the height increment of spruce understorey as a function of seedling height, site characteristics and canopy structure. Results: An admixture of pine and birch in the main canopy improves the height increment of understorey. When the stand basal area is 20 m2ha-1 height increment is twice as fast under pine and birch canopies, as compared to spruce. Height increment of understorey spruce increases with increasing seedling height. Between-stand and within-stand residual variation in the height increment of understorey spruces is high. The increment of 1/6 fastest- growing seedlings is at least 50% greater than the average. Conclusions: The results of this study help forest managers to regulate the density and species composition of the stand, so as to obtain a sufficient height development of the understorey. In pure and almost pure spruce stands, the stand basal area should be low for a good height increment of the understorey.[返回]

下载频数：16　　　　　　　上传时间：2014-07-30 　　　　　　　加入收藏

论文题目：Ingrowth, survival and height growth of small trees in uneven-aged Picea abies stands in southern Finland

全部作者： Kalle Eerik?inen1*, Sauli Valkonen2 and Timo Saksa3

期刊名称：Forest Ecosystems 2014年第1期

论文摘要：The purpose of the study was to analyse height growth, mortality, and ingrowth of individual small-sized trees in uneven-aged spruce-dominated stands. It was based on experimental data from 16 stands for a 15-year observation period including four measurements with a 5-year interval. In the data...[查看全部]

论文摘要：The purpose of the study was to analyse height growth, mortality, and ingrowth of individual small-sized trees in uneven-aged spruce-dominated stands. It was based on experimental data from 16 stands for a 15-year observation period including four measurements with a 5-year interval. In the data of this study, the heights of small-sized trees varied from 0.1 to about 9 m. Results showed that the growth of small trees was rather slow, particularly in the smallest size classes. With average growth rates it would take about 60 years for a freshly emerged spruce germinant to achieve 1.3 m in height. The stand density, site quality and selection cuttings affected the growth of small-sized spruces. Average five-year mortality rates for spruce, birch and pine were 17.0%, 40.9% and 33.9%, respectively. Annual ingrowth rates with the threshold height of 1.3 m for the three species were on average 30.4,2.8 and less than 0.1 trees per hectare, respectively. Even if, a selection cutting of modest intensity (25% of basal area removed on average) seemed to have accelerated the growth of small spruces, it is recommended that more intensive harvestings be applied to enhance the survival and growth of small spruces. It is also concluded that shade intolerant species like birch and pine do not seem to be capable of developing into viable undergrowth in spruce selection stands with their current levels of stand density.[返回]

下载频数：16　　　　　　　上传时间：2014-07-30 　　　　　　　加入收藏

论文题目：Local and generalized height-diameter models with random parameters for mixed, uneven-aged forests in Northwestern Durango, Mexico

全部作者： Sacramento CorraI-Rivas1*, Juan Gabriel ?lvarez-Gonzáilez2, Felipe Crecente-Campo2 and José Javier Corral-Rivas3

期刊名称：Forest Ecosystems 2014年第1期

论文摘要：Background: We used mixed models with random components to develop height-diameter (h-d) functions for mixed, uneven-aged stands in northwestern Durango (Mexico), considering the breast height diameter (d) and stand variables as predictors. Methods: The data were obtained from 44 permanent plots...[查看全部]

论文摘要：Background: We used mixed models with random components to develop height-diameter (h-d) functions for mixed, uneven-aged stands in northwestern Durango (Mexico), considering the breast height diameter (d) and stand variables as predictors. Methods: The data were obtained from 44 permanent plots used to monitor stand growth under forest management in the study area. Results: The generalized Bertalanffy-Richards model performed better than the other generalized models in predicting the total height of the species under study. For the genera Pinus and Quercus, the models were successfully calibrated by measuring the height of a subsample of three randomly selected trees close to the mean d, whereas for species of the genera Cupressus, Arbutus and Alnus, three trees were also selected, but they are specifically the maximum, minimum and mean d trees. Conclusions: The presented equations represent a new tool for the evaluation and management of natural forest in the region.[返回]

下载频数：10　　　　　　　上传时间：2014-07-30 　　　　　　　加入收藏

论文题目：Unsuspected implications arising from assumptions in simulations: insights from recasting a forest growth model in system dynamics

全部作者： Jerome K Vanclay

期刊名称：Forest Ecosystems 2014年第1期

论文摘要：Background; Familiarity with a simulation platform can seduce modellers into accepting untested assumptions for convenience of implementation. These assumptions may have consequences greater than commonly suspected, and it is important that modellers remain mindful of assumptions and remain...[查看全部]

论文摘要：Background; Familiarity with a simulation platform can seduce modellers into accepting untested assumptions for convenience of implementation. These assumptions may have consequences greater than commonly suspected, and it is important that modellers remain mindful of assumptions and remain diligent with sensitivity testing. Methods: Familiarity with a technique can lead to complacency, and alternative approaches and software can reveal untested assumptions. Visual modelling environments based on system dynamics may help to make critical assumptions more evident by offering an accessible visual overview and empowering a focus on representational rather than computational efficiency. This capacity is illustrated using a cohort-based forest growth model developed for mixed species forest. Results: The alternative model implementation revealed that untested assumptions in the original model could have substantial influence on simulated outcomes. Conclusions: An important implication is that modellers should remain conscious of all assumptions, consider alternative implementations that reveal assumptions more clearly, and conduct sensitivity tests to inform decisions.[返回]

下载频数：14　　　　　　　上传时间：2014-07-30 　　　　　　　加入收藏

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