Treesearch

Forests at risk to diseases caused by invasive Phytophthora pathogens can be grouped into two broad classes: those already invaded by the focal pathogen where disease has emerged or those at significant risk of invasion and subsequent emergence of disease. This dichotomy represents distinct management scenarios – treating after or before disease emerges – with a set of epidemiological, ecological, and practical management characteristics that determine optimal actions and associated costs. Here we present the initial outcomes from two management experiments aimed at restoring forest...

The Hawaiian Islands are among the most isolated and recently inhabited places on Earth. Discovered by Polynesian voyagers some 1000 years ago, people arrived to find unique wildlife and plants arrayed across a remarkable range of ecosystems. Polynesian settlers relied on traditional methods to cultivate canoe crops across the wide range of climate and soils. Early Hawaiian societies adapted to regular climate variations, including periods of extreme drought. Today, as drought events become more severe, contemporary communities must also learn to adapt.

Gross primary production (GPP) is the Earth’s largest carbon flux into the terrestrial biosphere and plays a critical role in regulating atmospheric chemistry and global climate. The Moderate Resolution Imaging Spectrometer (MODIS)-MOD17 data product is a widely used remote sensing-based model that provides global estimates of spatiotemporal trends in GPP. When the MOD17 algorithm is applied to regional scale heterogeneous landscapes, input data from coarse resolution land cover and climate products may increase uncertainty in GPP estimates, especially in high productivity tropical...

Measuring progress toward sustainability goals is a multifaceted task. International, regional, and national organizations and agencies seek to promote resilience and capacity for adaptation at local levels. However, their measurement systems may be poorly aligned with local contexts, cultures, and needs. Understanding how to build effective, culturally grounded measurement systems is a fundamental step toward supporting adaptive management and resilience in the face of environmental, social, and economic change. To identify patterns and inform future efforts, we review seven case studies...

Valley oak (Quercus lobata) is a majestic, endemic California native oak, found throughout California's foothills, valleys and flood plains. It is threatened because: Contracted range due to housing and agriculture. Low recruitment in existing stands as a function of land use and increased stress on existing trees and recruitment due to recent and projected climate change. Valley oak substantially shapes ecosystem functions and biodiversity where it occurs through above ground (e.g., provides shelter with cavities, and food with acorns) and below ground (e.g., soil stability and productivit...

Restoration of western dry forests in the USA often focuses on reducing fuel loads. In the range of the spotted owl, these treatments may reduce canopy cover and tree density, which could reduce preferred habitat conditions for the owl and other sensitive species. In particular, high canopy cover (≥70%) has been widely reported to be an important feature of spotted owl habitat, but averages of stand-level forest cover do not provide important information on foliage height and gap structure. To provide better quantification of canopy structure, we used airborne LiDAR imagery to identify...

The aim of this workshop breakout group session was to review significant gaps within each of three major themes (In-situ Conservation, Ex-situ Conservation, and Restoration of Species and Ecosystems) and to identify actionable solutions to move genetic conservation efforts forward. In order to identify solutions and action items for the tree conservation community, participants were asked to consider the session goals throughout the proceedings, provide examples of gaps in the field, and suggest actions to overcome roadblocks. To maximize participant feedback, a number of easel pads were...

In Nordamerika sind Wälder infolge von Einwandernden, internationalem Handel und Tourismus traditionell stark von Einschleppungen gebietsfremder invasiver Schadorganismen betroffen. Infolge von Globalisierung und Klimawandel gibt es aufgrund der Ähnlichkeiten von Klima, Flora und Fauna zwischen Europa und Nordamerika viele Parallelen.

Despite the mental and physical benefits of visiting natural areas, and increases in outdoor activity participation among U.S. youth overall in the past decade, outdoor access is skewed toward nonurban, nonminority populations. This environmental justice issue is particularly pronounced for minority youth in urban areas, such as the Los Angeles Basin. While decreased contact with nature has been associated with increased technology use, the popularity of new technologies and social media outlets presents novel opportunities to connect underserved urban youth with natural areas. Seven focus...

Soil moisture varies within landscapes in response to vegetative, physiographic, and climatic drivers, which makes quantifying soil moisture over time and space difficult. Nevertheless, understanding soil moisture dynamics for different ecosystems is critical, as the amount of water in a soil determines a myriad ecosystem services and processes such as net primary productivity, runoff, microbial decomposition, and soil fertility. We investigated the patterns and variability in in situ soil moisture measurements converted to plant‐available water across time and space under different...