https://www.fs.fed.us/pnw/pubs/journals/pnw_2002_franklin001.pdf

Disturbances and structural development of natural forest ecosystems with silvicultural implications, using Douglas-fir forests as an example

Review of methods for in situ leaf area index determination Part I. Theories, sensors and hemispherical photography

Predicting forest stand characteristics with airborne scanning laser using a practical two-stage procedure and field data

We investigated the influence of flood-induced channel changes on the hyporheic zone of 4th- and 5th-order reaches of a mountain stream network. Preflood versus postflood comparisons were made in three study reaches from well networks established before and reestablished after a major flood. Flood effects were scale dependent and varied with channel constraint and the dominant channel forming process. Large changes were observed in unconstrained stream reaches where channel incision drove large changes in subsurface flow paths and the extent of the hyporheic zone. However, subreach scale differences were apparent. In the lower portion of the studied reach, channel incision lowered the water table, leading to abandonment of secondary channels, and decreased the extent of the hyporheic zone that previously extended more than 30 m into the floodplain. In contrast, the extent of the hyporheic zone increased at the head of the studied reach where channel incision steepened head gradients through a meander bend. In another unconstrained reach, lateral channel jumps dramatically altered exchange flow paths. However, the extensive hyporheic zone was maintained throughout the reach. Less change was observed in the constrained stream reach where both the depth and area of sediment available to be reworked by the flood were limited by bedrock constraining the width of the valley floor. This flood dramatically changed the hyporheic zone at the three study sites and these physical changes are expected to be biologically important, considering the role of the hyporheic zone in stream ecosystem processes.

/pdf/floods-channel-change-and-the-hyporheic-zone-16izj5sd50.pdf

Floods, channel change, and the hyporheic zone

Recognition of the importance of land-use history and its legacies in most ecological systems has been a major factor driving the recent focus on human activity as a legitimate and essential subject of environmental science. Ecologists, conservationists, and natural resource policymakers now recognize that the legacies of land-use activities continue to influence ecosystem structure and function for decades or centuries—or even longer—after those activities have ceased. Consequently, recognition of these historical legacies adds explanatory power to our understanding of modern conditions at scales from organisms to the globe and reduces missteps in anticipating or managing for future conditions. As a result, environmental history emerges as an integral part of ecological science and conservation planning. By considering diverse ecological phenomena, ranging from biodiversity and biogeochemical cycles to ecosystem resilience to anthropogenic stress, and by examining terrestrial and aquatic ecosyst...

/pdf/the-importance-of-land-use-legacies-to-ecology-and-9j0xouwh2z.pdf

The Importance of Land-Use Legacies to Ecology and Conservation

Currently, commercial forestry applications of airborne scanning lidar are limited to geo-technical applications such as creation of digital terrain models for layout of roads or logging systems. We investigated the feasibility of predicting characteristics of forest stands with lidar data in a universityindustry partnership. Lidar lends itself well to such applications because it allows direct measurement of important structural characteristics of height and canopy closure. We found that lidar data can be used to predict the stand characteristics of height, basal area, and volume quite well. The potential for commercial applications appears bright. Lidar data can be used to estimate stand characteristics over large areas or entire forests. After the process is streamlined, it should be possible to provide maps of height, basal area, and volume in such areas within a few weeks of the lidar collection flight.

Predicting forest stand characteristics with airborne scanning lidar

Placing an upper bound to carbon (C) storage in forest ecosystems helps to constrain predictions on the amount of C that forest management strategies could sequester and the degree to which natural and anthropogenic disturbances change C storage. The potential, upper bound to C storage is difficult to approximate in the field because it requires studying old-growth forests, of which few remain. In this paper, we put an upper bound (or limit) on C storage in the Pacific Northwest (PNW) of the United States using field data from old-growth forests, which are near steady-state conditions. Specifically, the goals of this study were: (1) to approximate the upper bounds of C storage in the PNW by estimating total ecosystem carbon (TEC) stores of 43 old-growth forest stands in five distinct biogeoclimatic provinces and (2) to compare these TEC storage estimates with those from other biomes, globally. Finally, we suggest that the upper bounds of C storage in forests of the PNW are higher than current estimates of C stores, presumably due to a combination of natural and anthropogenic disturbances, which indicates a potentially substantial and economically significant role of C sequestration in the region. Results showed that coastal Oregon stands stored, on average, 1127 Mg C/ha, which was the highest for the study area, while stands in eastern Oregon stored the least, 195 Mg C/ha. In general, coastal Oregon stands stored 307 Mg C/ha more than coastal Washington stands. Similarly, the Oregon Cascades stands stored 75 Mg C/ha more, on average, than the Washington Cascades stands. A simple, area-weighted average TEC storage to 1 m soil depth (TEC 100 ) for the PNW was 671 Mg C/ha. When soil was included only to 50 cm (TEC50), the area-weighted average was 640 Mg C/ha. Subtracting estimates of current forest C storage from the potential, upper bound of C storage in this study, a maximum of 338 Mg C/ha (TEC100) could be stored in PNW forests in addition to current stores.

/pdf/potential-upper-bounds-of-carbon-stores-in-forests-of-the-270peghl5x.pdf

Potential upper bounds of carbon stores in forests of the pacific northwest

Assessing alternative allometric algorithms for estimating leaf area of Douglas-fir trees and stands.

Growth reduction in harvest-age, coniferous forests with residual trees in the western central Cascade Range of Oregon

Green tree retention, a practice based on ecosystem science, has been integrated into forest management as a working hypothesis, requiring research and monitoring to quantify its effects. We undertook a retrospective study of natural, two-aged forest stands on the Willamette National Forest to provide preliminary estimates of the effects of green tree retention on forest structure and yield. Fourteen stands in the western hemlock (Tsuga heterophylla (Raf.) Sarg.) zone (mostly dominated by Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco) were sampled using adjacent, paired plots: one with residual trees over a younger cohort (median age of younger cohort, 97 years) and one with only the younger cohort. The younger cohorts all had much higher densities of trees than typical of local Douglas-fir plantations. Basal area, volume, and mean annual increment (MAI) of the younger cohort all declined with increasing residual tree basal area. These relationships were best described by curvilinear models; the greatest effect per unit of residual tree basal area occurred at low residual tree levels (5n10 m 2 /ha). For 10 m 2 /ha residual tree basal area (equivalent to about 12 average (diameter at breast height 105 cm) residual trees per hectare), we predicted a 26% decline in younger cohort MAI (95% confidence interval: n30% to n22%).

/pdf/structure-and-yield-of-two-aged-stands-on-the-willamette-357pwllebh.pdf

Structure and yield of two-aged stands on the Willamette National Forest, Oregon: implications for green tree retention

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