Treesearch

The transition from Late Pleistocene to Holocene climates triggered biogeographical upheavals worldwide that included species’ range shifts, changes in community composition and structure, altered disturbance regimes, and development of new ecological interactions. The Great Basin, with its hundreds of high mountain ranges interspersed by broad basins, was a prominent stage on which such dynamics unfolded. Many plant and animal species remained scattered at low elevations throughout the Great Basin during the cold Late Pleistocene. Without significant displacements in latitude, they...

Forest managers working in dry forest ecosystems must contend with the costs and benefits of fire, and they are seeking forest management strategies that enhance the resilience of forests and landscapes to future disturbances in a changing climate. An interdisciplinary science team worked with resource managers and stakeholders to assess future forest ecosystem dynamics, given potential climatic changes and management strategies, across a 23,000-ha landscape in the Lake Tahoe basin of California and Nevada in support of the Lake Tahoe West Restoration Partnership. We projected forest...

We address the concerns that managed forest plantations may cause reductions of diversity of understory vegetation. We performed inventories of two mature ponderosa pine plantations in which multiple treatments were applied during plantation establishment. At stand age 35, we measured tree heights and diameters, understory plant cover and diversity, soil nutrients and chemical properties, and soil microbial biomass and diversity with phospholipid fatty acid. We found a significant, positive effect from both herbicide (H) and fertilizer (F) applications on subsequent overstory tree growth...

Concern for tree mortality and damage, and preferences for management interventions, reflect people’s values and cultures. We examine perceptions of tree diseases in two Indigenous communities to provide examples of the types of distress and attitudes that arise when tree diseases significantly damage cultural values. Summaries of yellow-cedar decline as perceived by Tlingit and Haida Alaska Natives and rapid ʻōhiʻa death (ROD) and Native Hawaiian culture underscore the interconnections between local people and local forests and the ways forest diseases can impart a loss of culture and...

This study evaluates the secondary successional pathways of Hawaiian lowland rainforest following anthropogenic disturbance. Whereas primary succession on lava flows has been well studied in Hawaii, secondary successional dynamics on disturbed habitats in the presence of nonnative species has been poorly researched and documented. Our study was based on two vegetation sampling efforts conducted on 200–400-year-old lava flows 2 and 27 years following a 400-hectare clearcutting operation in the Puna District of the southeast quadrant of Hawaii Island. Intact forest adjacent to the clearcut...

The Late Holocene Dry Period (LHDP, 3100-1800 cal yr BP) is well established as a period of extreme aridity across lowlands of the Great Basin (GB) yet little has been elaborated about high mountain conditions. Further, temperatures have not been comprehensively addressed at any elevation, although the period is often implied to have been warm. Despite a literature on the early Neoglaciation in the GB, conditions at high elevations have not been incorporated in previous treatments of the LHDP. We compile existing and new data on locations and ages for early Neoglacial advances in mountains...

Background The capacity of forest fuel treatments to moderate the behavior and severity of subsequent wildfires depends on weather and fuel conditions at the time of burning. However, in-depth evaluations of how treatments perform are limited because encounters between wildfires and areas with extensive pre-fire data are rare. Here, we took advantage of a 1200-ha randomized and replicated experiment that burned almost entirely in a subsequent wildfire under a wide range of weather conditions. We compared the impacts of four fuel treatments on fire severity, including two thin-only, a...

As disturbances continue to increase in magnitude and severity under climate change, there is an urgency to develop climate-informed management solutions to increase resilience and help sustain the supply of ecosystem services over the long term. Towards this goal, we used climate analog modeling combined with logic-based conditions assessments to quantify the future resource stability (FRS) under mid-century climate. Analog models were developed for nine climate projections for 1 km cells across California. For each model, resource conditions were assessed at each focal cell in comparison...

Development and redevelopment are important drivers of tree removal and canopy loss in urban landscapes. Local ordinances are often used to curtail tree removal, but punitive regulations alone may not be enough to reduce urban tree canopy loss in land development. In Florida (US), efforts to balance trees and development have often relied on fees and fines, but with a recent backlash against tree regulations and the fast pace of urban growth, we explored the possible role of incentives in urban tree policies. We interviewed 20 land developers across Florida to understand their perspectives...

Understanding and quantifying the resilience of forests to disturbances is increasingly important for forest management. Historical fire suppression, logging, and other land-uses have increased densities of shade tolerant trees and fuel buildup in the western United States, which has reduced the resilience of these forests to natural disturbances. One way to mitigate this problem is to use fuel treatments such as stand thinning and prescribed burning. In this study, we investigated changes in forest structure in the Lassen and Plumas National Forests of northern California following a...