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Summary Despite growing evidence that, on average, diverse forests tend to be more productive than species‐poor ones, individual studies often report strongly contrasting relationships between tree species richness and above‐ground wood production ( AWP ). In the attempt to reconcile these apparently inconsistent results, we explored whether the strength and shape of AWP –diversity relationships shifts along spatial and temporal environmental gradients in forests across Europe. We used tree ring data from a network of permanent forest plots distributed at six sites across Europe to estimate annual AWP over a 15‐year period (1997–2011). We then tested whether the relationship between tree species richness and AWP changes (i) across sites as a function of large‐scale gradients in climatic productivity and tree packing density and (ii) among years within each sites as a result of fluctuating climatic conditions. AWP –species richness relationships varied markedly among sites. As predicted by theory, the relationship shifted from strongly positive at sites where climate imposed a strong limitation on wood production and tree packing densities were low, to weakly negative at sites where climatic conditions for growth were most suitable. In contrast, we found no consistent effect of interannual fluctuations in climate on the strength of AWP –species richness relationships within sites. Synthesis . Our results indicate that the shape and strength of the relationship between tree diversity and forest productivity depends critically on environmental context. Across Europe, tree diversity shows the greatest potential to positively influence forest productivity at either end of the latitudinal gradient, where adverse climatic conditions limit productivity and lead to the development of less densely packed stands.

Tropical forests are global centres of biodiversity and carbon storage.Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified.Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent.The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity.

In the year 2011 the German Federal Government adopted its Forest Strategy 2020. This strategy includes 60 goal formulations in nine action fields. The present paper analyses to which extent the results of the German National Forest Inventory (BWI) prove achievements of those of the 60 goals, which are quantitatively verifiable. The results reveal that forestry in Germany in general meets its own standard of multi-functionality, securing that forests fulfil manifold demands of the society. However, while the objectives of nature and climate protection are on track for being achieved, the prospects for objectives related to employment, income and value added are less encouraging. Total forest area and forest growth are increasing, forests currently constitute a carbon sink, and the naturalness and structural diversity of forests are growing. Also the high but sustainable use of the wood fosters currently the income of and employment in forest enterprises and timber industries. But the ongoing regeneration of forest stands predominantly with deciduous tree species is expected to cause a long-term lack of faster growing and higher valuated coniferous stands. The resulting lack of highly demanded softwood of small or medium-sized diameters will raise problems to timber industries. Moreover, shrinking timber production due to a decreasing share of coniferous forests has adverse consequences not only from the economic point of view. It will also decrease the climate-friendly use of wood products, in particular due to the foregone substitution effect. The results of the study also show that BWI is an indispensable source of information for forest politics and forest science particularly in view of its long-term time series. The preservations of time series must be kept in mind whenever changes in the methods of BWI are considered.

Wood is considered to be a renewable resource. However, steep increases in production followed by a peak and subsequent decline have been characteristic of natural forest-based wood industries in many countries. An assessment was made to determine any discernible global trend in wood extraction from natural forests. This was done using published data on global production from various wood sources, including plantations, planted forests and trees outside forests. Global wood supply from natural forests peaked around 1989 and has been in decline since. A growing planted tree supply has been making up the gap between total roundwood demand and natural forest supply. These data suggest a declining role for natural forests in global wood production, with the long term sustainability of wood supply derived from purpose-cultivated trees rather than natural forest sources. Where these planted trees lower demand for wood from natural forests this will provide opportunities to reduce resource conflict in natural forests, apply more precautionary prescriptions where logging does occur, and increase the use of natural forests for biodiversity conservation and other ecosystem services such as carbon storage.

Balancing increasing demand for wood products while also maintaining forest biodiversity is a paramount challenge. Europe’s Biodiversity and Forest Strategies for 2030 attempt to address this challenge. Together, they call for strict protection of 10% of land area, including all primary and old growth forests, increasing use of ecological forestry, and less reliance on monocultural plantations. Using data on country wide silvicultural practices and a new database on strict forest reserves across Europe, we assess how triad forest zoning could help meet these goals. Our analysis reveals that zoning in Europe is overwhelmingly focused on wood production, while there has been little concomitant protection of forests in strict reserves. Moreover, most strict forest reserves are < 50 ha in size, likely too small to capture the minimum dynamic area necessary to sustain many taxa. We outline research priorities to meet future demands for timber while minimizing the impact on native biodiversity.

At least one climate model predicts severe reductions of rainfall over Amazonia during this century. Long-term throughfall exclusion (TFE) experiments represent the best available means to investigate the resilience of the Amazon rainforest to such droughts. Results are presented from a 7 yr TFE study at Caxiuanã National Forest, eastern Amazonia. We focus on the impacts of the drought on tree mortality, wood production and above-ground biomass. Tree mortality in the TFE plot over the experimental period was 2.5% yr⁻¹ compared with 1.25% yr⁻¹ in a nearby control plot experiencing normal rainfall. Differences in stem mortality between plots were greatest in the largest (> 40 cm diameter at breast height (dbh)) size class (4.1 % yr⁻¹ in the TFE and 1.4% yr⁻¹ in the control). Wood production in the TFE plot was 30% lower than in the control plot. Together, these changes resulted in a loss of 37.8 ± 2.0 Mg carbon (C) ha⁻¹ in the TFE plot (2002-2008), compared with no change in the control. These results are remarkably consistent with those from another TFE (at Tapajós National Forest), suggesting that eastern Amazonian forests may respond to prolonged drought in a predictable manner.

Long distance cell-to-cell communication is critical for the development of multicellular organisms. In this respect, plants are especially demanding as they constantly integrate environmental inputs to adjust growth processes to different conditions. One example is thickening of shoots and roots, also designated as secondary growth. Secondary growth is mediated by the vascular cambium, a stem cell-like tissue whose cell-proliferating activity is regulated over a long distance by the plant hormone auxin. How auxin signaling is integrated at the level of cambium cells and how cambium activity is coordinated with other growth processes are largely unknown. Here, we provide physiological, genetic, and pharmacological evidence that strigolactones (SLs), a group of plant hormones recently described to be involved in the repression of shoot branching, positively regulate cambial activity and that this function is conserved among species. We show that SL signaling in the vascular cambium itself is sufficient for cambium stimulation and that it interacts strongly with the auxin signaling pathway. Our results provide a model of how auxin-based long-distance signaling is translated into cambium activity and suggest that SLs act as general modulators of plant growth forms linking the control of shoot branching with the thickening of stems and roots.

The current study emphasizes the inherent shortcomings of laws and policy approaches that are based on the premise that by increasing wood production, much more emission credits can be achieved by using wood in alternative uses. The article aims to exploit the financing of emission reductions, discuss how carbon sinks held in forest resources can be activated, traded, and financed, and explain how Turkiye's forest carbon potential can be exploited. To make a comparative analysis of the situation of Turkiye at global level, Russian’s potential for carbon sequestration and its trade have been dealt with as a comparison by following quantitative research methodology.  In this research, the calculation method has been used to determine the number of houses that are likely to be built in rural areas using wood materials, e.g., the construction of 100,000 houses with a construction area of 100 m2 per year. Consequently, the forest carbon generated by alternative scenarios contributes positively to the emission balance sheet, as well as climate change mitigation through carbon emission trade despite all legal and technical constraints. Although both countries have similar shortcomings of obtaining carbon credits and its trade, of course Russia has a promising situation in comparison with Turkiye with respect to the amount of carbon sequestered and the likelihood of its trade potential at global level.

The Amazon Basin experiences severe droughts that may become more common in the future. Little is known of the effects of such droughts on Amazon forest productivity and carbon allocation. We tested the prediction that severe drought decreases litterfall and wood production but potentially has multiple cancelling effects on belowground production within a 7-year partial throughfall exclusion experiment. We simulated an approximately 35-41% reduction in effective rainfall from 2000 through 2004 in a 1 ha plot and compared forest response with a similar control plot. Wood production was the most sensitive component of above-ground net primary productivity (ANPP) to drought, declining by 13% the first year and up to 62% thereafter. Litterfall declined only in the third year of drought, with a maximum difference of 23% below the control plot. Soil CO2 efflux and its 14C signature showed no significant treatment response, suggesting similar amounts and sources of belowground production. ANPP was similar between plots in 2000 and declined to a low of 41% below the control plot during the subsequent treatment years, rebounding to only a 10% difference during the first post-treatment year. Live aboveground carbon declined by 32.5 Mg ha−1 through the effects of drought on ANPP and tree mortality. Results of this unreplicated, long-term, large-scale ecosystem manipulation experiment demonstrate that multi-year severe drought can substantially reduce Amazon forest carbon stocks.

The present study aims to identify the relations between the wood production (m3 per year) of the black pine (Pinus nigra Arnold.) and its habitat characteristics in the Eastern Mediterranean Region. A total of 120 samplings with different aspects, site altitudes, and site classes were studied. In each sample area, at least 5 trees were designated, and soil samples were taken by excavating earth pits. Certain characteristics of the soil samples were identified in the laboratory environment. The relations between the dominant height values of the trees in the sample areas and soil, climate, and physiographic factors were analyzed using correlation analysis, multiple regression analysis, and artificial neural network methods. Significant relations between the wood production values of the trees in the sample areas and slope from physiographic habitat characteristics, average annual temperature from climate characteristics, and pH and total carbonate from soil characteristics were found. The wood production of black pine was explained by multiple regression analysis at a level of 22.4% and by artificial neural network method at 72%.