查看更多>>摘要：? 2022Forest area increase has been characteristic to the Eastern Baltic region since the early twentieth century. The emergence of new forest areas in significant amounts changes the visual and ecological character of landscapes and affects forest management decisions. The aim of this study was to investigate how emerging spatial patterns and stand characteristics of new forest areas impact forests in Latvia. Four study areas were selected in Latvia – Skrunda, Bauska, Skujene and Kaunata to analyze new and stable forest areas. Inside these four areas, 27,205 forest compartments were analyzed from new forests and 93,902 compartments in stable forests for reference. New and stable forest areas were mapped for the period of 1967–2017. Latvian State Forest register database provided compartment-level characteristics for new and stable forests. Descriptive statistics was used to analyze differences in tree species composition, ownership structure and management restrictions; and GIS methods – to assess compartment accessibility by roads. Spatial pattern metrics were calculated using Morphological Spatial Pattern Analysis in Guidos Toolbox 2.6. Results show that the majority of new forest areas have emerged from spontaneous afforestation, this was especially pronounced in Kaunata area (only 5% of new forest areas were planted). Scots pine, Norway spruce and two birch species comprised the majority in stable forest areas compared to new forest areas, where the proportions of dominant tree species were more evenly distributed. Spatial pattern analysis showed that the emergence of new forest areas has contributed to the homogenization of forest pattern with increasing Core area, reducing Edge and Islet (isolated patch) proportion. 93–99% of new forest areas identified in this study were not state-owned. Compartment accessibility was very good for all four study areas in Latvia, with 60–80% of stands being located closer than 500 m from roads. This study demonstrated that management of such small, spatially scattered and young forest compartments can be problematic. Since the majority or Latvia's private forest owners’ holdings are smaller than 50 ha, the lack of resources and education as well physical factors impede successful involvement of these numerous small owners in sustainable management efforts.
查看更多>>摘要：? 2022 Elsevier B.V.Conversion from natural forest to timber plantation is an important cause of pristine forests loss. These changes alter community structure and cause a decrease in the diversity of plant communities. Leaf functional traits, which are an important defensive strategy, might also be influenced by such alterations. Altogether, shifts from natural forest to timber plantation may lead to profound changes in plant-plant and plant-animal interactions, including herbivory and the relative abundance of different feeding guilds, an important aspect of forest ecosystem function and community dynamics. In this study, we assessed insect herbivore damage in saplings of four native tree species in the understory of natural forests and two types of ca. 80-year-old timber plantations. We measured leaf damage by the most common feeding guilds in over 9000 leaves from 200 saplings. We first compared herbivory between natural forest and plantations, and we then analyzed the drivers of herbivory and of the two most common guilds – chewers and miners – using several indices of forest structure and leaf traits as predictors. Total herbivory did not change among forest types, but it showed some variation in two of the four species. Herbivory decreased with increasing species richness and increased with increasing basal area of conspecific and heterospecific trees. Leaf damage caused by chewers increased with leaf thickness, while damage caused by miners showed the opposite relationship. On an ecological level, our findings support expectations from the resource concentration hypothesis and on the role of leaf traits in mediating the impact of insect feeding guilds on leaf herbivory. On an applied level, these results suggest that timber plantations can support similar levels of ecosystem processes than natural forests decades after their establishment. Allowing the regeneration of a diverse understory in plantation forests should be implemented to favor ecosystem dynamics close to those of the original forests.
查看更多>>摘要：? 2022 Elsevier B.V.The authors regret two errors: (1) In Eq. (9), df should have been nb: [Formula presented] where nb is the sample size of biomass dataset. (iv) calculate the p-value of the χ2 statistic, using the right tail of a χ2 distribution with df = 1 for Eq. (7) and df = 2 for Eq. (8), degrees of freedom. The null hypothesis of homoscedasticity is rejected if p < 0.05.(2) In Table 2, weighting procedure 4, step (iii), the residual term in the model expression was missing. The correct expression should have been: [Formula presented]. Despite these textual errors, the analyses were correctly conducted and, therefore, the results were not affected. The authors apologise for this inconvenience.
查看更多>>摘要：? 2022 Elsevier B.V.Ultramafic rain forests in New Caledonia evolved on some of the most nutrient impoverished soils globally and are some of the slowest-growing tropical forests known. This study aimed to determine nutrient stocks and elucidate the biogeochemical cycling of nutrients in a remnant lowland rain forest in southern New Caledonia. Based on an inventory of a 1-ha permanent plot, exhaustive plant tissue sampling was undertaken of all large trees (diameter at breast height ≥ 15 cm) in a 0.25-ha subset of the plot in tandem with collecting 100 soil samples. All samples were analyzed for major nutrient concentrations and the results show that most of the magnesium was contained in the soil (96.9%), whereas a large fraction of calcium (46.5%) and phosphorus (16.0%), and the majority of potassium (81.5%) were contained in the standing biomass. This study has revealed how tightly these soil-derived nutrients are cycling in this system. Ultimately, this information will be essential for efforts to restore rain forest in New Caledonia, where the biomass (and contained nutrients) has been removed.
NSTL
Elsevier