Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 144-157). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 73-77). Also available on the World Wide Web.

Forest stands were studied to determine if old-growth forest structure could be mimicked in younger stands via overstory manipulation. Cover and species composition of understory plants were systematically sampled in sixteen thinned second-growth stands and sixteen adjacent unthinned second-growth Douglas fir (Pseudotsuga menziesii (Mirabel) Franco.) stands. The stands were thinned twenty-four to thirteen years ago. These were compared to seven nearby old-growth stands. Thinned and unthinned stands had matching elevations, aspect, and soils, yet differed primarily in management treatment. Leaf area indices were determined for these stands. Thinned stands differed from the old-growth and unthinned stands in having significantly higher cover values and species numbers, apparently resulting from increased light to the forest floor and a greater variety of microhabitats created by thinning. Young unthinned and old-growth stands were comparable in terms of cover and richness, but differed in species composition. Diversity indices showed no difference in species diversity between the three types of stands. Ordination of the species/sample data using Detrended Correspondence Analysis showed that understory species composition of the young unthinned and thinned stands was nearly identical. Species composition of old-growth stands differed from thinned and unthinned stands. The ordination indicated that age of the stands, structure of the canopy layers and climate were major determining factors in the species composition of the understory plant communities. Management manipulation of the second growth stands did not yield stands with understory vegetation communities that mimicked those of old-growth stands. The conclusions of this study were: 1) Shrub cover increased with thinning as compared to unthinned and old-growth stands. 2) Thinning increased the species richness of the stands, without increasing the number of exotics. 3) Diversity was not altered by thinning. Old-growth, thinned and unthinned stands did not differ in diversity values. 4) Patterns of community composition in thinned stands were more similar to unthinned equivalent stands than to nearby old-growth. / Graduation date: 1996

The potential of airborne LiDAR technology to quantify forest structure within eucalypt forests has been evaluated with a focus on the understorey stratum. To achieve this, three studies have been undertaken using multiple (4) LiDAR datasets acquired over three test areas located in Wedding Bells State Forest, Coffs Harbour, Australia. Initially, the effects of sensor configuration were evaluated using field measurements collected from three structurally and topographically differing field plots (40 x 90 m areas). Results indicated that canopy height profiles derived from LiDAR data at the plot scale were largely unaffected by a change in platform altitude from 1000 to 3000 m (p &gt 0.05). In addition, the derivation of individual tree attributes was found to be highly sensitive to the density of LiDAR observations whilst higher platform altitudes showed an increased proportion of single returns over forested areas. In the second study, an innovative field based approach was developed to sample the structure of the understorey (horizontally and vertically) for LiDAR validation purposes. Using two separate LiDAR datasets, this research confirmed that mean understorey height and understorey cover can be effectively mapped in areas of low to medium canopy cover whilst no significant relationship (p &gt 0.05) was identified between field and LiDAR estimates of maximum understorey height. In the third study, an optimised LiDAR beam interception model was developed and validated, and then applied to assess the interaction of extrinsic and intrinsic factors of the LiDAR survey. This demonstrated that the probability of beam interception through the forest canopy can be affected by factors both intrinsic (e.g. crown cover) and extrinsic (e.g. scan angle) to the structure of the canopy. Overall, the results of this research indicate that optimising the sensor configuration is important to the derivation of particular forest structural attributes and significantly, there is potential for LiDAR technology to provide quantitative and spatially detailed estimates of key understorey attributes such as mean height and cover.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 96-118).

This study investigated the transplantation of understory plants within the Cu-Ni smelterdamaged urban forest of Sudbury, Ontario, Canada, to increase plant biodiversity in an area where natural colonization of understory species is delayed. The goal of my study was to evaluate establishment of 16 m2 vegetation mats along a gradient of smelter disturbance and to relate successful establishment to abiotic and biotic site characteristics. Specific investigations were conducted to determine whether soil quality influenced root growth and transplant establishment. Variables associated with smelter emissions and soil temperature were the best predictors of successful transplant establishment of understory plant species, but relationships were species specific. Also, root growth was not limited to organic soils of the transplant mat and roots were able to grow into receptor site soil. Knowledge of environmental factors influencing establishment will help to determine site locations and to select species to introduce when transplanting understory species in future reclamation projects.

"The pre-settlement distribution and character of Wimmera Buloke woodlands are described based on historical data including early parish plans. It is suggested the open structure of these woodlands was maintained by relatively frequent fire. The floristic composition of the most intact Wimmera Buloke woodland remnants was intensively surveyed. Five floristic communities are described based on computer-based analysis of species presence data. Eight 'pre-settlement Buloke woodland types' are described based on surface soil texture categories and average annual rainfall zones. Native daisies, chenopods and shrubs are components of the understory that differentiate the 'pre-settlement Buloke woodland types'. [...] A series of experiments was undertaken with the aim of determinig the factors responsible for the paucity of Allocasuarina luehmannii regeneration in remnant Wimmera bushland." / Master of Applied Science

"The pre-settlement distribution and character of Wimmera Buloke woodlands are described based on historical data including early parish plans. It is suggested the open structure of these woodlands was maintained by relatively frequent fire. The floristic composition of the most intact Wimmera Buloke woodland remnants was intensively surveyed. Five floristic communities are described based on computer-based analysis of species presence data. Eight 'pre-settlement Buloke woodland types' are described based on surface soil texture categories and average annual rainfall zones. Native daisies, chenopods and shrubs are components of the understory that differentiate the 'pre-settlement Buloke woodland types'. [...] A series of experiments was undertaken with the aim of determinig the factors responsible for the paucity of Allocasuarina luehmannii regeneration in remnant Wimmera bushland." / Master of Applied Science

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 210-228). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 67-74). Also available on the World Wide Web.