Decomposition and nitrogen release from decomposing woody roots in coniferous forests of the Pacific Northwest: a chronosequence approach

2001 ◽  
Vol 31 (2) ◽  
pp. 246-260 ◽  
Author(s):  
Hua Chen ◽  
Mark E Harmon ◽  
Robert P Griffiths

Decomposition of woody roots in Sitka spruce (Picea sitchensis (Bong.) Carrière), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and ponderosa pine (Pinus ponderosa P. Laws. ex C. Laws.) dominated forests in Oregon, U.S.A. was studied using a chronosequence. Roots of five coniferous species were excavated from stumps with ages up to 46 years old. In order of increasing decomposition rate constant (k) the species were Douglas-fir < Sitka spruce < lodgepole pine (Pinus contorta Dougl. ex Loud.) < western hemlock (Tsuga heterophylla (Raf.) Sarg) < ponderosa pine. Variation in the proportion of bark, wood, and resin cores was correlated to these differences. Root wood showed the highest k, root bark the second, and resin cores the lowest. The occurrence of resin cores in woody roots of Douglas-fir, Sitka spruce, and lodgepole pine greatly slowed the decomposition of these species. White rots occurred frequently in ponderosa pine and lodgepole pine, whereas brown rots mostly appeared in Douglas-fir and Sitka spruce. Species with white rot had a higher k than those with brown rot. Decomposing woody roots started to release N after 20–30% mass loss, a point when the dead root C/N ratio averaged 140.

1993 ◽  
Vol 8 (2) ◽  
pp. 67-70 ◽  
Author(s):  
E. E. Nelson ◽  
Rona N. Sturrock

Abstract Several species of conifers were outplanted around infected stumps in Oregon and British Columbia to measure their susceptibility to laminated root rot caused by Phellinus weirii. Grand fir (Abies grandis) experienced nearly 30% mortality caused by P. weirii. Douglas-fir (Pseudotsuga menziesii) mortality exceeded 20%. Noble fir (A. procera), Sitka spruce (Picea sitchensis), giant sequoia (Sequoiadendron giganteum), western hemlock (Tsuga heterophylla), and ponderosa pine (Pinus ponderosa) mortality averaged less than 10%. Western white pine (P. monticola) and lodgepole pine (P. contorta) mortality was less than 1%. Phellinus weirii did not cause mortality of western redcedar (Thuja plicata) or redwood (Sequoia sempervirens). Apparent susceptibility, based on mortality over 17-20 growing seasons, was similar to that recorded in past field observations. West. J. Appl. For. 8(2):67-70.


2006 ◽  
Vol 82 (5) ◽  
pp. 723-732 ◽  
Author(s):  
Alan Vyse ◽  
Christine Ferguson ◽  
Suzanne W Simard ◽  
Tamaki Kano ◽  
Pasi Puttonen

The effects of partial cutting on seedling growth of three conifer species were studied at a very dry, hot interior Douglas-fir site near Kamloops, British Columbia. Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), and ponderosa pine (Pinus ponderosa Dougl. ex. P. & C. Laws.) seedlings were planted in mechanically prepared 50 cm × 50 cm patches under different canopy conditions created by harvesting 60% of the original stand volume. The prepared areas were selected to represent canopy closures from open to closed, slopes from 0 to 60%, and all aspects. After six years, survival of Douglas-fir, lodgepole pine and ponderosa pine was 78%, 76% and 70%, respectively. Light level had a strong influence on survival and condition. Growth of all species increased linearly with light, and was greatest for lodgepole pine, followed by ponderosa pine and Douglas-fir. Multiple regression analysis showed that six-year seedling size was most significantly affected by total light, and only occasionally by aspect, slope, or crown closure. The best models explained 53%, 47% and 42% of the variation in diameter of lodgepole pine, ponderosa pine, and Douglas-fir, respectively. Natural abundance 13C was positively correlated with light and soil moisture availability, reflecting higher photosynthetic capacity of all species in the wetter, open canopy conditions. Patterns in isotopic discrimination also indicated greater water use efficiency of Douglas-fir and ponderosa pine than lodgepole pine under low light conditions. Underplanting stands thinned to a basal area of less than 15m2 per ha offers a solution to regeneration difficulties on hot, dry Interior Douglas-fir sites. Key words: partial cutting, Douglas-fir, lodgepole pine, ponderosa pine, light, soil moisture, 13C, growth, survival, Opax Mountain Silvicultural Systems Project


1999 ◽  
Vol 9 (4) ◽  
pp. 223 ◽  
Author(s):  
Richard Everett ◽  
John Lehmkuhl ◽  
Richard Schellhaas ◽  
Pete Ohlson ◽  
David Keenum ◽  
...  

Snag numbers and decay class were measured on a chronosequence of 26 wildfires (ages 1-81 years) on the east slope of the Cascade Range in Washington. Snag longevity and resultant snag densities varied spatially across burns in relation to micro-topographic position. Longevity of snags < 41cm dbh was greater for thin-barked Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa) and lodgepole pine (Pinus contorta) than thick-barked Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa). With larger diameter snags, however, Douglas-fir persisted longer than Engelmann spruce. The time period required for recruitment of soft snags > 23 cm dbh was estimated to exceed snag longevity for ponderosa pine, Englemann spruce, lodgepole pine, and subapline fir, causing an “on-site gap” in soft snags for these species. Snags of Douglas-fir ≥ 41 cm dbh stood for a sufficient time (40% standing after 80 years) to potentially overlap the recruitment of soft snags ≥ 23 cm dbh from the replacement stand. Providing continuity in soft snags following stand-replacement events would require a landscape-scale perspective, incorporating adjacents stands of different ages or disturbance histories. Results suggest that standards and guidelines for snags on public forest lands need to be sufficiently flexible to accomodate both disturbance and stand development phases and differences in snag longevity among species and topographic positions.


2015 ◽  
Vol 45 (11) ◽  
pp. 1607-1616 ◽  
Author(s):  
Monica T. Rother ◽  
Thomas T. Veblen ◽  
Luke G. Furman

Climate change may inhibit tree regeneration following disturbances such as wildfire, altering post-disturbance vegetation trajectories. We implemented a field experiment to examine the effects of manipulations of temperature and water on ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings planted in a low-elevation, recently disturbed setting of the Colorado Front Range. We implemented four treatments: warmed only (Wm), watered only (Wt), warmed and watered (WmWt), and control (Co). We found that measures of growth and survival varied significantly by treatment type. Average growth and survival was highest in the Wt plots, followed by the Co, WmWt, and Wm plots, respectively. This general trend was observed for both conifer species, although average growth and survival was generally higher in ponderosa pine than in Douglas-fir. Our findings suggest that warming temperatures and associated drought are likely to inhibit post-disturbance regeneration of ponderosa pine and Douglas-fir in low-elevation forests of the Colorado Front Range and that future vegetation composition and structure may differ notably from historic patterns in some areas. Our findings are relevant to other forested ecosystems in which a warming climate may similarly inhibit regeneration by dominant tree species.


2019 ◽  
Vol 49 (11) ◽  
pp. 1471-1482
Author(s):  
Woongsoon Jang ◽  
Bianca N.I. Eskelson ◽  
Louise de Montigny ◽  
Catherine A. Bealle Statland ◽  
Derek F. Sattler ◽  
...  

This study was conducted to quantify growth responses of three major commercial conifer species (lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson), interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco), and spruce (white spruce (Picea glauca (Moench) Voss) and hybrid spruce (Picea engelmannii Parry ex. Engelm. × Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carrière))) to various fertilizer blends in interior British Columbia, Canada. Over 25 years, growth-response data were repeatedly collected across 46 installations. The fertilizer blends were classified into three groups: nitrogen only; nitrogen and sulfur combined; and nitrogen, sulfur, and boron combined. The growth responses for stand volume, basal area, and top height were calculated through absolute and relative growth rate ratios relative to a controlled group. Fertilizer blend, inverse years since fertilization, site index, stand density at fertilization, and their interactions with the fertilizer blend were used as explanatory variables. The magnitude and significance of volume and basal area growth responses to fertilization differed by species, fertilizer-blend groups, and stand-condition variables (i.e., site index and stand density). In contrast, the response in top height growth did not differ among fertilization blends, with the exception of the nitrogen and sulfur fertilizer subgroup for lodgepole pine. The models developed in this study will be incorporated into the current growth and yield fertilization module (i.e., Table Interpolation Program for Stand Yields (TIPSY)), thereby supporting guidance of fertilization applications in interior forests in British Columbia.


1997 ◽  
Vol 12 (3) ◽  
pp. 69-73 ◽  
Author(s):  
R. Rose ◽  
D. L. Haase ◽  
F. Kroiher ◽  
T. Sabin

Abstract This is the final summary of two studies on the relationship between root volume and seedling growth; early results were published previously. Survival, growth, and stem volume were determined for 2+0 ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) seedlings after 8 growing seasons. For each species, seedlings from three seedlots were assigned to one of three root-volume categories [<4.5 cm3 (RV1), 4.5-7 cm3 (RV2), and >7 cm3 (RV3) for ponderosa pine; <9 cm3 (RV1), 9-13 cm3 (RV2), and >13 cm3 (RV3) for Douglas-fir]. On a dry harsh ponderosa pine site on the eastern slopes of Mt. Hood in Oregon, where gopher and cattle damage decreased the number of seedlings, more seedlings in the highest root-volume category survived (70%) than in the smaller root-volume categories (62% and 50%). Douglas-fir on a good site in the Coast Range of Oregon showed significantly greater height and stem volume for the largest root-volume category, whereas annual shoot growth and survival did not differ. Root volume is one of several potentially useful criteria for predicting long-term growth and survival after outplanting. West. J. Appl. For. 12(3):69-73.


1999 ◽  
Vol 77 (8) ◽  
pp. 1053-1076 ◽  
Author(s):  
H B Massicotte ◽  
R Molina ◽  
L E Tackaberry ◽  
J E Smith ◽  
M P Amaranthus

Seedlings of Abies grandis (Dougl.) Lindl. (grand fir), Lithocarpus densiflora (Hook. & Arn.) Rehd. (tanoak), Pinus ponderosa Dougl. ex Laws. (ponderosa pine), Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir), and Arbutus menziesii Pursh (madrone) were planted in mixture and monoculture in soil collected from three adjacent forest sites in southwestern Oregon (a clearcut area, a 25-year-old Douglas-fir plantation, and a mature 90- to 160-year-old Douglas-fir - pine forest) to determine the effect of host tree diversity on retrieval of ectomycorrhizal morphotypes. In this greenhouse bioassay, 18 morphotypes of mycorrhizae were recognized overall from all soils with a total of 55 host-fungus combinations: 14 types with ponderosa pine, 14 with Douglas-fir, 10 with tanoak, 10 with grand fir, and 7 for madrone. Four genus-specific morphotypes were retrieved (three on ponderosa pine and one on Douglas-fir), even in mixture situations, demonstrating selectivity of some fungal propagules by their respective host. Five types were detected on all hosts, but not necessarily in soils from all sites. The remaining nine types were associated with two, three, or four hosts, which indicates a wide potential for interspecific hyphal linkages between trees. More morphotypes were retrieved from the monoculture treatments compared with the mixture treatments, although the differences were not significant. Several examples of acropetal replacement of one fungus by another (interpreted as succession) were recorded on all hosts during the course of the experiment. These results illustrate the importance of different host species in maintaining ectomycorrhizal fungus diversity, especially fungi with restricted host range, and the strong potential for fungal linkages between trees in forest ecosystems.Key words: fungal succession, fungal communities, compatibility, Arbutus menziesii, Pseudotsuga menziesii, Pinus ponderosa, Abies grandis, Lithocarpus densiflora.


2020 ◽  
Vol 29 (11) ◽  
pp. 1042
Author(s):  
Tyler R. Hudson ◽  
Ryan B. Bray ◽  
David L. Blunck ◽  
Wesley Page ◽  
Bret Butler

This work reports characteristics of embers generated by torching trees and seeks to identify the important physical and biological factors involved. The size of embers, number flux and propensity to ignite spot fires (i.e. number flux of ‘hot’ embers) are reported for several tree species under different combinations of number (one, three or five) and moisture content (11–193%). Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis), western juniper (Juniperus occidentalis) and ponderosa pine (Pinus ponderosa) trees were evaluated. Embers were collected on an array of fire-resistant fabric panels and trays filled with water. Douglas-fir trees generated the highest average ember flux per kilogram of mass loss during torching, whereas grand fir trees generated the highest ‘hot’ ember flux per kilogram of mass loss. Western juniper produced the largest fraction of ‘hot’ embers, with ~30% of the embers generated being hot enough to leave char marks. In contrast, only 6% of the embers generated by ponderosa pine were hot enough to leave char marks. Results from this study can be used to help understand the propensity of different species of tree to produce embers and the portion of embers that may be hot enough to start a spot fire.


1997 ◽  
Vol 12 (4) ◽  
pp. 115-121 ◽  
Author(s):  
Andris Eglitis ◽  
Paul E. Hennon

Abstract This study describes feeding damage by porcupines (Erethizon dorsatum) in precommercially thinned young growth stands of Sitka spruce (Picea sitchensis) and western hemlock (Tsuga heterophylla) on Mitkof Island in central southeast Alaska. We examined 641 trees from 54 sampling plots along transect lines in three 12 to 20 yr old stands. Porcupine feeding was monitored each spring and fall from 1985 to 1987. Four categories of feeding damage are described: complete girdling of the bole, partial girdling (bole scars), branch clipping, and "tasting wounds" (small basal bole scars). Sitka spruce, the primary crop tree in these thinned stands, sustained significantly higher damage (52% of trees affected) than western hemlock (26% of trees affected). Porcupine feeding was greater on taller than shorter Sitka spruce. Although only 8 of 59 trees initially girdled in 1985 were killed, many later sustained additional feeding damage. Following the 1987 season 3 yr after thinning, nearly 30% of the spruce and 14% of the western hemlock crop trees had been partially or completely girdled. Issues deserving future attention include the role of thinning in predisposing stands to porcupine damage, methods of population assessment, and mechanisms of host selection by porcupines. West. J. Appl. For. 12(4):115-121.


2001 ◽  
Vol 79 (11) ◽  
pp. 1349-1357 ◽  
Author(s):  
Cameron G Lait ◽  
Sarah L Bates ◽  
Karen K Morrissette ◽  
John H Borden ◽  
Allison R Kermode

Radiography is a valuable tool for assessing quality of conifer seeds, but it cannot differentiate between aborted seeds and seeds that have been emptied by western conifer seed bug (Leptoglossus occidentalis Heidemann) feeding. We tested three biochemical marker-based assays that were developed to identify L. occidentalis damage to seeds of Douglas-fir, Pseudostuga menziesii (Mirb.) Franco, for their use in lodgepole pine, Pinus contorta var. latifolia Engelmann. The three assays included measurement of storage protein reserve depletion, immunodetection of fragments of insoluble (crystalloid) storage proteins, and immunodetection of L. occidentalis salivary proteins. Aborted seeds contained significantly less soluble and insoluble protein than seeds that were fed on by L. occidentalis. Polyclonal antibodies raised against 11S globulin crystalloid proteins or L. occidentalis salivary gland extracts only immunoreacted with proteins in seeds exposed to L. occidentalis feeding. In a single-blind test, antibody raised against salivary-gland extracts correctly distinguished between undamaged full seeds, unfilled aborted seeds, and seeds fed on by L. occidentalis. Immunodetection of L. occidentalis salivary proteins was also performed on seeds of Abies amabilis Dougl. ex J. Forbes, Tsuga heterophylla (Raf.) Sarg., Picea sitchensis Bong (Carr.), Pinus ponderosa Lawson, and Pinus monticola Dougl. ex D. Don. For all species, immunoreactive polypeptides were only detected in seeds fed on by L. occidentalis. These biochemical marker-based techniques could help researchers and seed orchard managers estimate seed losses caused by L. occidentalis in commercial seed orchards and natural forest stands.Key words: Leptoglossus occidentalis, saliva, biochemical markers, polyclonal antibody, immunodetection, Pinus contorta.


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