Treesearch

Scotch broom (Cytisus scoparius: (L.) Link), a native European perennial shrub, was introduced to the U.S. before the turn of the century as an ornamental for its bright yellow, pea-like flower. The plant found the western U.S. maritime zone to be an ideal habitat, thus it soon escaped from cultivation, and became an invasive weed now widely distributed from northern California to British Columbia. The massive monocultures that Scotch broom forms replace desirable species and cause allergy problems when flowering in spring. This has elevated it to one of the most important weeds in the...

Forest Nursery Notes (FNN) is a nursery news and literature service that is distributed free of charge to over 1,200 cooperators in the United States, Canada, and other foreign countries. This issue's topics include: fertigation, holdover nursery stock, late-season fertilization, and bird damage.

The first part of this article in the Summer 2009 issue covered basic mineral nutrition, the 3 components of a fertigation system, and the chemical calculations forformulating your own custom fertigation solutions. In this second and final part, we'll discuss types of fertilizer injectors, fertigation scheduling, and how to check injector function and determine exactly how much liquid fertilizer is going on your crop.

The choice of container is one of the most important considerations when growing or ordering native plants for a restoration project. Container characteristics affect not only growth and production efficiencies in the nursery, they can also have important consequences after outplanting. The challenging conditions on restoration sites require containers with characteristics that are significantly different from standard containers used for horticultural crops. Unfortunately, plant specifications for many restoration projects are written using traditional horticultural pot dimensions, and we...

Seed Ecology III was held in Salt Lake City, Utah in June 2010, sharing the latest research on all aspects of seed ecology. Our meeting was organized around the theme "Seeds and Change." We welcomed contributions in any area of seed ecology. Our agenda also aimed to create bridges between seed ecology and plant conservation, restoration ecology, and global change research.

We assessed the risk of impaired condition of the nearly 3700 5th-level watersheds in the contiguous 48 states containing the national forests and grasslands that make up the U.S. Forest Service's National Forest System (NFS). The assessment was based on readily available, relatively consistent nationwide data sets for a series of indicators representing watershed stressors and resources at risk of watershed impairment. Using a set of weights that express the relative importance of the indicators, a summary measure of relative risk of watershed impairment was computed for each entire...

Recent data from the USDA Forest Service Forest Inventory and Analysis (FIA) program have documented spatial and temporal patterns of drought-related mortality across woodlands of the Southwest (Shaw et al. 2005). In the early 1990s, FIA collected data on forested land now included in Grand Staircase-Escalante National Monument (GSENM or the Monument) as part of a comprehensive periodic inventory of Utah (O'Brien 1999). In 2000, FIA implemented an annual inventory system in Utah, measuring 10 percent of the full plot complement each year. These data provide a baseline of conditions just...

Phellinus tremulae is an important fungal decay agent common to aspen and a critical component to the cavity-nesting bird complex found in western aspen stands. Little information exists on the conditions that facilitate infection and spread of P. tremulae in aspen forests. I used Forest Inventory and Analysis (FIA) data to explore the relationships of several tree and stand characteristics to the presence and frequency of P. tremulae in aspen measured across several western states of the United States. Results suggest a strong relationship between tree age, tree diameter, and compacted...

A complex of drought, insects, and disease is causing widespread mortality in multiple forest types across western North America. These forest types range from dry Pinus-Juniperus woodlands to moist, montane Picea-Abies forests. Although large-scale mortality events are known from the past and considered part of natural cycles, recent events have largely been attributed to climate change. We use data from the Forest Inventory and Analysis program to assess the onset, extent, and severity of impacts of mortality events that have occurred since the mid-1990s.

This study develops near range-wide predictive distribution maps for six important conifer species (Pseudotsuga menziesii, Tsuga heterophylla, Pinus contorta, Thuja plicata, Larix occidentalis, and Picea glauca) using forest inventory data collected across the United States and Canada. Species model accuracies are compared with range size using a rank scoring system. A suite of climate and topographic predictor variables are used to investigate environmental constraints that limit species range and quantify relationships between species predicted probability of occurrence and dominance at...