Forests2015, 6(2), 280-292; doi:10.3390/f6020280 - published 26 January 2015 Show/Hide Abstract
Abstract: Many of the forest soils in the Intermountain West are deficient in several nutrients, including nitrogen (N), potassium (K), sulfur (S) and boron (B) and these deficiencies may impact tree resistance to insect attack. Two potential techniques for manipulating tree resistance are fertilization and thinning. We examined fertilization (both alone and in conjunction with stand thinning). Conifer resistance to bark beetles involves a three-step response, the first stage of which is resin flow. Rapid resin flow can prevent the colonization of bark beetles within a tree. Fertilization with low levels of N resulted in an increase in resin flow while high levels of N did not significantly increase resin flow in treated trees. Thinning did not result in higher concentrations of foliar K or B but did result in higher concentrations of foliar N and S. The highest concentrations of foliar N and S consistently occurred in the trees from thinned treatments, regardless of fertilization. There was a negative correlation between tree growth and resin flow one year following treatments. Increasing available nutrient levels to trees (either through fertilization or stand density management) may result in modified resistance parameters that must be considered when making management decisions.
Forests2015, 6(1), 271-279; doi:10.3390/f6010271 - published 20 January 2015 Show/Hide Abstract
Abstract: Extensive mortality of eastern hemlock, Tsuga canadensis (L.) Carrière, resulting from infestation by hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), has occurred throughout the eastern United States. Although imidacloprid treatment can reduce tree mortality, its effectiveness can be influenced by several factors including tree water stress. The relationship between water stress and infestation rates is unknown, and an understanding of these could greatly increase the efficiency of management for this invasive insect. The primary objective of this study was to assess water stress at three levels of hemlock woolly adelgid infestations. Water stress was measured monthly for 13 months in eastern hemlocks classified as <25%, 25%–75%, and >75% infested. The highest level of water stress was found in those trees with hemlock woolly adelgid infestation levels greater than 75%. The lowest level of water stress was found in those trees with less than 25% hemlock woolly adelgid infestation levels. Knowledge of these effects can contribute to development of more effective chemical management strategies.
Forests2015, 6(1), 252-270; doi:10.3390/f6010252 - published 16 January 2015 Show/Hide Abstract
Abstract: Research activities combining lidar and radar remote sensing have increased in recent years. The main focus in combining lidar-radar forest remote sensing has been on the retrieval of the aboveground biomass (AGB), which is a primary variable related to carbon cycle in land ecosystems, and has therefore been identified as an essential climate variable. In this review, we summarize the studies combining lidar and radar in estimating forest AGB. We discuss the complementary use of lidar and radar according to the relevance of the added value. The most promising prospects for combining lidar and radar data are in the use of lidar-derived ground elevations for improving large-area biomass estimates from radar, and in upscaling of lidar-based AGB data across large areas covered by spaceborne radar missions.
Forests2015, 6(1), 244-251; doi:10.3390/f6010244 - published 15 January 2015 Show/Hide Abstract
Abstract: Since the early design of activities to reduce emissions from deforestation and forest degradation in developing countries (REDD+) under the United Nations Framework Convention on Climate Change (UNFCCC), the need to engage local communities and indigenous groups in monitoring and reporting has been recognized. REDD+ has advanced under the UNFCCC negotiations, but most countries still need to define formally what the role of communities in their national monitoring systems will be. Previous research and experiences have shown that local communities can effectively contribute in the monitoring of natural resources. This editorial introduces a Special Issue of Forests which discusses the implications of and potential for including community based monitoring (CBM) in monitoring and benefit-sharing systems in REDD+. It outlines the main points of the nine contributions to the Special Issue which cover a wide geographical area and report on projects and research which engages more than 150 communities from eight different countries from Africa, Asia and Latin America. The editorial summarizes how the articles and reports build further understanding of the potential of CBM to contribute to the implementation, monitoring and distribution of benefits in REDD+. It also discusses the results of an on-going opinion survey on issues related to CBM and its relation to benefit sharing, which indicates that there is still disagreement on a number of key elements.
Forests2015, 6(1), 225-243; doi:10.3390/f6010225 - published 13 January 2015 Show/Hide Abstract
Abstract: The public’s demand for more and better forest landscapes is increasing as scenic forest tours flourish in China, especially in the capital, Beijing. How to improve the quality of scenic forests has become one of the greatest concerns of urban foresters. Although numerous studies have focused on scenic forest management, to date, no reports have been found on developing a quality assessment index system for scenic forest assessment. In this study, a simple and scientific index system was established using an analytical hierarchy process (AHP) to quantitatively assess scenic forest quality. The index system is composed of four scales: individual tree landscape quality, in-forest landscape quality, near-view forest landscape quality and far-view landscape quality. The in-forest landscape quality was determined by horizontal and vertical stand structures, species composition and under-canopy landscape traits. Near-view forest landscape quality was mainly determined by patch characteristics, seasonal change, visibility, color change of patches and stand age class. To test the validity of our quality assessment index system, scenic forests in Xishan were used as a case study. The results show that near-view forest landscape was the most important scale for the overall quality of the scenic forest, according to the priorities of the criterion layer, and the second most important scale was far-view forest landscape. Seasonal change, patch color contrast, patch distribution and patch shape accounted for 52.2% of the total of 13 indices in the near-view forest landscape. The integrated quality of scenic forests in Xishan was at an average level, and the in-forest landscape, near-view landscape and far-view landscape had below average quality.
Forests2015, 6(1), 203-224; doi:10.3390/f6010203 - published 9 January 2015 Show/Hide Abstract
Abstract: Theinternationaldebates on REDD+ and the expectations to receive results-based payments through international climate finance have triggered considerable political efforts to address deforestation and forest degradation in many potential beneficiary countries. Whether a country will receive such REDD+ payments is largely contingent on its ability to effectively address the relevant drivers, and to govern the context-dependent agents and forces responsible for forest loss or degradation. Currently, many REDD+ countries are embarking on the necessary analytical steps for their national REDD+ strategies. In this context, a comprehensive understanding of drivers and their underlying causes is a fundamental prerequisite for developing effective policy responses. We developed a methodological framework for assessing the drivers and underlying causes of deforestation and use the Fako Division in Southern Cameroon as a case study to test this approach. The steps described in this paper can be adapted to other geographical contexts, and the results of such assessments can be used to inform policy makers and other stakeholders.