Oviposition Site Selection of Anoplophora glabripennis in Sugar Maple (Acer saccharum) and Its Gnawing Nidus Oviposition Habits

[Objective] The paper was to explore the oviposition site selection of Anoplophora glabripennis in sugar maple and its gnawing nidus oviposition habits. [Method] Through field and indoor rearing observation, the oviposition site selection of A. glabripennis in sugar maple was studied, and the gnawing nidus oviposition habits were analyzed. [Result] The height of oviposition site of A. glabripennis in sugar maple, the number observation holes （gnawing nidus oviposition points） and bark thickness in oviposition site showed linear correlation with diameter of branch at breast height. The gnawing nidus oviposition habit of A. glabripennis in sugar maple was mainly divided into 4 stages： gnawing nidus site selection, gnawing nidus, oviposition and nidus sealing, the duration from gnawing nidus to nidus sealing was（38.29±16.47）min. [Conclusion] The study provided reference for comprehensive prevention of A. glabripennis in greening tree species sugar maple, as well as further study on reproductive behavior and regulation mechanism of A. glabripennis.

Effect of hot-water extraction of sugar maple on organosolv delignification and lignin recovery

This paper reported a gradual disassembly of the chemical components of hardwood,starting with hot-water extraction(HWE)for the removal of hemicelluloses,followed by organosolv delignification to remove the lignin.Under mild acid conditions,in addition to hemicelluloses,lower molecular weight lignin fractions were removed(~15%of the total lignin)in the HWE pre-treatment;also,the cleavage of the acid-labile lignin-carbohydrate bond took place to some extent.As a result,the HWE pretreatment promoted the subsequent delignification process and facilitated the lignin recovery from the spent liquor,in terms of higher delignification efficiency and higher purity of the lignin recovered from the spent liquor.The effects of the HWE pre-treatment prior to the delignification process were investigated in this study for both the oxygen-pressurized acetone-water(AWO)and the ALCELL processes,with focuses on the delignification efficiency and the properties of the lignin recovered from the process spent liquor.

Growth trends and environmental drivers of major tree species of the northern hardwood forest of eastern North America

The future health and productivity of tree species in the northern hardwood forest of eastern North America are uncertain considering changes in climate and pollution loading there.To better understand the trajectory of the northern hardwood forest,we studied the growth of three tree species emblematic of it:sugar maple(Acer saccharum Marsh),American beech(Fagus grandifolia Ehrh.),and yellow birch(Betula alleghaniensis Britton),plus a fourth species,red maple(Acer rubrum L.),whose abundance has increased in the region.We also analyzed the link between growth and several factors for690 trees in 45 plots throughout Vermont,USA:tree age and size,site elevation,and climate and acid deposition variables.Throughout their chronologies(1945-2014),all four species exhibited increasing growth followed by plateaued growth indicative of a maturing forest.For all species,summer moisture was positively correlated with growth,summer temperature was negatively associated with growth,and winter moisture or snow were positively correlated with growth.This last association was expected for sugar maple.However,our data suggest that winter snowpack may be more broadly relevant in sustaining tree growth in a region where snow has historically insulated the soil from freezing that can damage roots and lead to reduced aboveground growth.Measures of pollution deposition were also correlated with growth for all species except American beech—a species with documented tolerance to pollutant inputs.Of the four species studied,red maple had the fewest associations with environmental variables,which suggests that it may be less susceptible to growth reductions as the climate changes.

Forest biodiversity, relationships to structural and functional attributes, and stability in New England forests

Background： Forest biodiversity is the foundation of many ecosystem services, and the effect of biodiversity on ecosystem functioning and processes （BEF） has been a central issue in biodiversity studies. Although many hypotheses have been developed to interpret global gradients of biodiversity, there has not been complete agreement on mechanisms controlling biodiversity patterns and distributions. Differences may be due to limited observation data and inconsistencies of spatial scales in analysis. Methods： In this study, we take advantage of USDA Forest Service forest inventory and analysis （FIA） data for exploring regional forest biodiversity and BEF in New England forests. The FIA data provide detailed information of sampled plots and trees for the region, including 6000 FIA plots and more than 33,000 individual trees. Biodiversity models were used to analyze the data. Results： Tree species diversity increases from the north to the south at a rate about 2-3 species per latitudinal degree. Tree species diversity is better predicted by tree height than forest age or biomass. Very different distribution patterns of two common maple species, sugar maple （Acer sdcchorum） and red maple （Acer rubrum）, highlight the vulnerability of sugar maple and its potential replacement by red maple on New England landscapes. Red maple generally already outperforms sugar maple, and will likely and continuously benefit from a changing climate in New England. Conclusions： We conclude that forest structure （height） and resources （biomass） are more likely foundational characteristics supporting biodiversity rather than biodiversity determining forest productivity and/or biomass. The potential replacement of red maple for sugar maple in the New England areas could affect biodiversity and stability of forest ecosystem functioning because sugar maple plays important ecological roles distinct from red maple that are beneficial to other tree species in northern hardwood forests. Such a change may not affect forest resilience in terms of forest productivity and biomass as these are similar in red maple and sugar maple, however, it would almost certainly alter forest structure across the landscape.