Leaf Area, Stemwood Volume Growth, and Stand Structure in a Mixed-Species, Multi-Aged Northern Conifer Forest

Tree- and stand-level leaf area (LA) - stemwood volume growth relationships were explored in mixed-species, multi-aged northern conifer stands dominated by Tsuga canadensis (L.) Carr. (eastern hemlock), Abies balsameu (L.) Mill. (balsam fir), and Piceu rubens Sarg. (red spruce). A T. cunudensis LA model was developed to supplement published equations for A. bulsumeu and P. rubens. Sapwood area was an effective T. cunudensis LA surrogate, though nonsapwood-based models using stem cross-sectional area and modified live crown ratio produced results comparable to sapwood-based models. Equations for predicting tree-level stemwood volume increment (AVINC) were derived, and implied growth efficiencies (GE) were used to assess magnitude and pattern of GE change between strata and species. AVINC was effectively modeled using LA alone, and the slightly peaking GE - LA relationships approximated those previously conceptualized for shade-tolerant species. A. bulsamea and trees in upper strata were most efficient. T. canadensis maximum GE occurred at a higher LA than A. balsumea or P. rubens, and A. bulsameu maximum GE was less than that previously observed in even-aged stands. Age was not a significant predictor of tree-level GE or stemwood increment. Multi-aged, stand-level stemwood volume increment - leaf area index (LAI) relationships were assessed on 0.02-ha plots dominated by T. cunudensis, A. bulsumeu, and P. rubens. Structures conceptually associated with even-, two-, and multi-aged stands were documented. Inter-plot structural variability was attributed to incomplete stand-level conversion to a balanced condition, and a hybrid single-tree and group selection regeneration method. Plot-level stemwood volume increment (PAVINC) was modeled for all plots combined using LAI and proportion of midstory leaf area (LAC). Two clusters of plots with different basal area, LAI, LAC, and PAVINC were identified. Average diameter distributions within each cluster were typical of multi-aged stands. Within-cluster analysis indicated that quantified structural variables did not improve estimation of PAVINC from LAI, though additional study is warranted due to small sample size. LAI -relative density relationships suggested that plot-level stocking and PAVINC could be increased. This study extends physiologically based silviculture research to mixed-species, multi-aged stands of shade-tolerant species, and confirms the usefulness of LA - growth relationships for describing and evaluating stand dynamics

The Matinee Girl

Lady dressed in 1950\u27s attirehttps://scholarsjunction.msstate.edu/cht-sheet-music/11509/thumbnail.jp

Diameter-Limit Cutting and Silviculture in Northeastern Forests: A Primer for Landowners, Practitioners and Policymakers

https://digitalcommons.library.umaine.edu/fac_monographs/1113/thumbnail.jp

Título: Ellos están vivos

Ellos están vivos / Margarita Kenefic. - Mención honorífica del Premio Nueva Dramaturgia Guatemalteca 2010Premios: Premio Nueva Dramaturgia Guatemalteca 201

Timber harvesting on fragile ground and impacts of uncertainties in the operational costs

Forested wetlands with high water tables are sensitive to disruption from harvesting yet support commercially desired tree species like northern white-cedar. Winter harvest was conducted in Maine, USA, to compare operational costs and productivity of cut-to-length harvesting in cedar (fragile soil) and non-cedar stands (mixed wood, sturdy soil), evaluate uncertainties in harvesting costs and influential factors, and forecast time for post-harvest recovery to pre-harvest volumes. Operational costs were calculated using detailed time and motion studies. Operational costs for the cedar stands were higher than non-cedar. Regression models were developed for harvesters, forwarders, and self-loading trucks; number of logs per cycle was a common factor. Sensitivity analysis showed the dependence of operational costs on labor and fuel costs. Forest Vegetation Simulator projections were used to assess harvest sustainability and suggested the time required to regrow harvested merchantable volume is comparable to cutting cycles recommended for similar treatments in the region. Predicted growth rates exceed those reported regionally on similar sites, suggesting additional study of post-harvest response is warranted. Results highlight site constraints on both operational and stand productivity in lowlands and will be useful for timber harvesting decision-making and forest management planning if combined with assessment of residual stand growth response

Alternative Large-Scale Conservation Visions for Northern Maine: Interviews with Decision Leaders in Maine

Based on confidential interviews with 21 decision leaders in Maine, Elizabeth Baldwin, Laura Kenefic, and Will LaPage examine the complexity of the conflicts over alternate visions for large-scale conservation in Maine. Exploring models that may be useful for policymakers grappling with competing values for Maine’s forests, they present four alternatives: national forests, new U.S. forest service models, forest heritage areas, and the British national park model. The authors found that the leaders interviewed agreed about the need for some level of conservation, but did not completely agree on how this might happen and where the decision-making power should lie

Do forest reserves help maintain pollinator diversity and pollination services in tropical agricultural highlands? A case study using Brassica rapa as a model

IntroductionHabitat loss and fragmentation have negative impacts on pollinator populations and thus on the pollination services they provide. Negative effects can be lessened by the presence of forest remnants that serve as refuges and sources of food for pollinators. However, few studies have analyzed the influence of highly heterogeneous agricultural landscapes (as commonly found in many developing countries), on pollination services.MethodsWe compared native bee diversity, pollination visitation, and fruit set of Brassica rapa L. between two land use conditions (sites maintaining more than 15% of the original forest coverture [Moderately Modified], and sites with less of 10% [Highly Modified]) in the highlands of Guatemala.ResultsNative bee diversity was higher in HM areas, although social bees were more abundant in MM sites. We did not find differences in pollinator visitation rate between conditions. HM sites were mainly visited by honeybees (Apis mellifera Linnaeus), while native bees and syrphid flies were more frequent in the MM condition. Fruit set was significantly higher in MM sites and was positively affected by natural forest areas. Experiments on pollen limitation and on pollinator efficiency stressed the importance of native pollinators in fruit production, especially in moderately modified areas.DiscussionOur results highlight the role of forest remnants for the provision of pollination services in tropical agricultural highlands and underline the relevance of appropriate management of introduced bees such as A. mellifera

Todos los loros se llaman igual

Ellos están vivos / Margarita Kenefic. - Mención honorífica del Premio Nueva Dramaturgia Guatemalteca 2010Premios: Premio Nueva Dramaturgia Guatemalteca 201

MP764: Field Manual for Managing Eastern White Pine Health in New England

This manual provides basic information for identifying and evaluating important health problems of eastern white pine in New England. The health problems include: • White pine weevil • White pine blister rust • Caliciopsis canker • White pine bast scale • White pine needle damage • Red rot or Red-ring rot In addition to providing descriptions of symptoms, signs, and risk factors, recommendations for white pine silviculture are described for managing stands for low densities and crop trees.https://digitalcommons.library.umaine.edu/aes_miscpubs/1039/thumbnail.jp