Other Forestry and Forest Sciences Commons^™

Shape Indexes For Semi-Automated Detection Of Windbreaks In Thematic Tree Cover Maps From The Central United States, Greg C. Liknes, Dacia M. Meneguzzo, Todd A. Kellerman

USDA Forest Service / UNL Faculty Publications

Windbreaks are an important ecological resource across the large expanse of agricultural land in the central United States and are often planted in straight-line or L-shaped configurations to serve specific functions. As high-resolution (i.e., <5 m) land cover data sets become more available for these areas, semi-or fully-automated methods for distinguishing windbreaks from other patches of trees are needed for use with thematic raster data sets. To address this need, we created three shape indexes: a morphology-based index that we have named the Straight and Narrow Feature Index (SNFI), a windbreak sinuosity index, and an area index indicating the occupied fractional area of a bounding box. The indexes were tested in two study areas: (1) a riparian area dominated by sinuous bands of trees but mixed with row crop agriculture and (2) an agricultural area with a mix of straight-line and L-shaped windbreaks. In the riparian area, a Kruskall–Wallis rank sum test indicated class differences for all three indexes, and pairwise comparisons indicate windbreaks and riparian trees are separable using any of the three indexes. SNFI also produced significant differences between windbreaks oriented in different directions (east–west vs. north–south). In the agricultural area, the Kruskall–Wallis rank sum test indicated differences between classes for all three indexes, and pairwise comparisons show that all class pairs have significant differences for at least one index, with the exception of L-shaped windbreaks vs. non-windbreak tree patches. We also used classification trees to objectively assign representative samples of tree patches to classes using both single indexes and multiple indexes. Classes were correctly assigned for more than 90% of the samples in both the riparian and agricultural study areas. In the riparian area, combining indexes did not improve accuracy compared to using SNFI alone, whereas in the agricultural area, combining the three indexes produced the best result. Thematic data sets derived from high-resolution imagery are becoming more available, and extracting useful information can be a challenge, partly due to the large amount of data to assess. Calculating the three shape indexes presented can assist with efficient identification of candidate windbreaks and as such, hold good promise for value-added analysis of tree function in the central United States.

The Effects Of Early Pruning On The Near-Ground Branch Density Of Four Live Fencing Species, Aric Devens

Dissertations, Master's Theses and Master's Reports

Crop losses in home gardens greatly impact the wellbeing of rural West African families. Herbivory by migratory or local livestock represents a significant source of crop loss. Live-fencing gardens with thorny hedges is a low-cost and sustainable strategy for reducing losses due to herbivory. However, guidance on the establishment of thorny hedges is inconsistent, poorly publicized, and often anecdotal. Therefore, this study evaluated the effects of three early pruning treatments on near-ground branch density of four thorny species: Vachellia nilotica, Senegalia laeta, Senegalia mellifera, and Prosopis juliflora. Physical measurements and photographic data indicated that after one growing season, V. …

Alley Farming : New Vision For Western Australian Farmland, Ted Lefroy, Phil Scott

Journal of the Department of Agriculture, Western Australia, Series 4

Alley farming is a system where crops and pastures are grown in the alleys between rows of trees and shrubs. The concept is new to Western Australia but one that is likely to become more familiar over the next few years. The objective is to use trees and shrubs to decrease the environmental side effects of agriculture, such as erosion and salinity while increasing farm profit through the direct and indirect value of the trees.

This article describes some examples of alley farming in Western Australia and discusses the challenge of getting the right tree species and layout to maximise …

Bluegum Timberbelts For Profitable Landcare, Peter Eckersley

Journal of the Department of Agriculture, Western Australia, Series 4

Revegetation with tasmanian bluegums in wide-spaced timberbelts appears to offer high returns, especially in areas where high winds cause crop and stock losses and where land can be saved from salinity and wwaterlogging.

In the South Coast and South-WestRegions, timberbelts will complement existing enterprises and so optimise overall land use. Graziers should be able to maintaine their stock numbers while creating an on-farm superannuation package.

The Department of Conservation and Land Management has been a major player in the development of bluegum timberbelts, but a few farmers are now adapting this concept to better suit their needs. Initial results are …