Effects of Population Structure and Cone Production on Outcrossing Rates in Engelmann Spruce and Subalpine Fir

Evolution ◽  
1987 ◽  
Vol 41 (1) ◽  
pp. 124 ◽  
Author(s):  
Kathleen L. Shea
Keyword(s):  
Population Structure ◽  
Subalpine Fir ◽  
Cone Production ◽  
Engelmann Spruce ◽  
Outcrossing Rates

Effects of harvesting on fine root biomass and decomposition in an Engelmann spruce – subalpine fir forest

2003 ◽  
Vol 33 (5) ◽  
pp. 847-853 ◽  
Author(s):  
Sylvia E Welke ◽  
Graeme D Hope ◽  
Gary A Hunt
Keyword(s):  
Root Biomass ◽  
Fine Root ◽  
Timber Harvesting ◽  
High Elevation ◽  
Fine Root Biomass ◽  
Nutrient Concentrations ◽  
Root Dynamics ◽  
Subalpine Fir ◽  
Root Longevity ◽  
Engelmann Spruce

The effect of timber harvesting on the biomass, nutrient standing crop, and decomposition of fine roots (<2 mm) was studied in a high elevation, Engelmann spruce (Picea engelmannii Parry ex Engelm.) – subalpine fir (Abies lasiocarpa (Hook.) Nutt.) forest. Root dynamics were compared in openings of different sizes. The sequential core method was used to collect fine root samples over 4 years. Differences in fine root biomass between opening sizes were most significant for the active fine root portion and were most pronounced in the fall compared with the spring. Active fine root biomass was significantly lower in the 10-ha clearcuts (164 kg/ha) compared with control plots (275 kg/ha). Furthermore, active fine root biomass was often lower in the 1.0-ha opening than in the 0.1-ha and control plots. A similar trend was established for inactive fine root biomass, although this was not consistent over sampling years. Nutrient concentrations of K, but no other elements, were higher in control plots. Nutrient standing crops, however, followed trends observed in fine root biomass. In the 10-ha clearcuts, the largest changes in fine root biomass occurred at the edge of the opening. The findings suggest that small (<10 ha) cutblocks may maintain greater fine root longevity.

Indicators of population viability in red spruce, Picea rubens. II. Genetic diversity, population structure, and mating behavior

2000 ◽  
Vol 78 (7) ◽  
pp. 941-956 ◽  
Author(s):  
Om P Rajora ◽  
Alex Mosseler ◽  
John E Major
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Picea Rubens ◽  
Red Spruce ◽  
Past Century ◽  
Stage Of Development ◽  
Outcrossing Rates ◽  
Population Sizes ◽  
Allozyme Loci ◽  
Filled Seeds

Red spruce (Picea rubens Sarg.) has become increasingly rare across large portions of its range in eastern North America as a result of a general and widespread decline over the past century. Genetic diversity, population genetic structure, outcrossing rates in the filled seeds, and actual inbreeding levels were characterized in five small, isolated, remnant red spruce populations from the disjunct northwestern limits of its range in Ontario and five populations from the larger, more extensive Maritime populations of Nova Scotia and New Brunswick to determine genetic and reproductive status, to provide some benchmarks for monitoring genetic changes resulting from isolation and restricted population sizes, and to assist the development of restoration and conservation strategies. Thirty-seven allozyme loci coding for 15 enzymes were used for genetic diversity assessments, and six of the most polymorphic loci were used for mating system determination. On average, 29.1% (95% criterion) of the loci were polymorphic, the number of alleles per locus was 1.60, and the observed and expected heterozygosities were 0.097 and 0.100, respectively. The Ontario populations were comparable to or slightly less genetically variable than those from the Maritimes. Only 4.7% of the detected genetic variation was among stands; the remainder was among individuals within stands. The Maritime populations were genetically less differentiated from each other than those in Ontario. With the exception of three Maritime populations clustering tightly in one group, there was no clear separation of Ontario red spruce populations from Maritime red spruce populations based on genetic distance as well as canonical discriminant analyses. The average multilocus (tm) and single-locus (ts) population outcrossing rates were 0.595 and 0.558, respectively, indicating a comparatively high tolerance for inbreeding up to the filled seed stage of development in red spruce. The Ontario populations, on average, showed higher outcrossing rates (tm = 0.654, ts = 0.641) than the Maritime populations (tm = 0.535, ts = 0.475). Individual family outcrossing rates were similar to their respective population outcrossing rates and no significant differences were observed among families within populations for the multilocus estimates. When such high levels of inbreeding in filled seeds were combined with the proportions of empty (post-pollination-aborted) seeds, it appears that actual inbreeding levels may vary from 48 to 86%. The highest inbreeding levels occurred in the smallest, most isolated Ontario populations and in those populations most likely to have been affected by poorer pollination conditions. Allozyme variation indicates that in the short term, extant remnants of Ontario red spruce have maintained their genetic diversity and integrity. For artificial restoration of red spruce in Ontario, local seed sources could be used without undue concern over losses of genetic diversity. However, over the longer term, genetic drift and inbreeding may be expected to result in further losses of genetic diversity and (or) reproductive fitness if population sizes, numbers, and distribution continue to decline.Key words: Picea rubens, allozymes, gene conservation, restoration, genetic diversity, population structure, outcrossing rates, inbreeding.

scholarly journals Natural and Advance Regeneration of Engelmann Spruce and Subalpine Fir Compared 21 Years After Site Treatment

1980 ◽  
Vol 56 (2) ◽  
pp. 55-57 ◽  
Author(s):  
L. J. Herring ◽  
R. G. McMinn
Keyword(s):  
Natural Regeneration ◽  
Mineral Soil ◽  
Poor Performance ◽  
Abies Lasiocarpa ◽  
Subalpine Fir ◽  
Engelmann Spruce ◽  
Advance Regeneration ◽  
Residual Tree ◽  
Mean Current ◽  
Picea Engelmanni

The mean height of Engelmann spruce (Picea engelmanni Parry) advance growth 21 years after release by overstorey harvesting and residual tree felling, was eight times that of natural regeneration established following brush blade scarification. Subalpine fir (Abies lasiocarpa (Hook.) Nutt.) advance growth was nine times taller than natural regeneration established on scarified soil. Mean current annual height increment of Engelmann spruce and subalpine fir advance growth was 39 and 34 cm, respectively, compared with only 7 cm for natural regeneration on scarified soil. The performance gap does not appear to be narrowing. The poor performance of natural regeneration on mineral soil exposed by blade scarification is attributed to removal of organic and top mineral soil horizons beyond the immediate reach of seedlings. These soil layers remained available to the advance growth. Consideration should be given to preserving advance growth when scarification may be inappropriate.

Simulated conversion of unmanaged interior spruce-subalpine fir stands to a regulated uneven-aged structure

2000 ◽  
Vol 76 (3) ◽  
pp. 465-474 ◽  
Author(s):  
Craig Farnden
Keyword(s):  
Old Growth ◽  
Individual Tree ◽  
Subalpine Fir ◽  
High Q ◽  
Engelmann Spruce ◽  
Management Objectives ◽  
Individual Tree Growth ◽  
Interior Spruce ◽  
Growth Attributes ◽  
Tree Growth Model

A localized version of the Forest Vegetation Simulator (FVS) individual tree growth model was developed to simulate stand level impacts under a variety of uneven-aged management regimes in old-growth interior spruce-subalpine fir forests near Prince George British Columbia. Options for using uneven-aged management to satisfy a range of management objectives were simulated using different sets of BDq regulation parameters, and by varying species composition and rules for reserve trees. The greatest timber yields were attained by promoting the highest possible spruce component, using high q ratios, low to moderate maximum diameters and 20 to 25 year cutting cycles, and allowing no reserves. Using strategies to promote stand structures maintaining some old-growth attributes resulted in much lower timber yields. Key words: white spruce, Engelmann spruce, subalpine fir, uneven-aged management, BDq regulation, simulated yield

Segregation of allozyme loci in megagametophytes of Engelmann spruce and subalpine fir

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Kathleen L. Shea
Keyword(s):  
Natural Populations ◽  
Segregation Ratio ◽  
Colorado Front Range ◽  
Abies Lasiocarpa ◽  
Front Range ◽  
Subalpine Fir ◽  
Polymorphic Loci ◽  
Engelmann Spruce ◽  
Low Levels ◽  
Allozyme Loci

Segregation ratios and linkage of 10 allozyme loci were examined in haploid megagametophytes obtained from natural populations of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) in the Colorado Front Range. For data pooled over trees, the 1:1 segregation ratio expected at Mendelian loci was obtained for five polymorphic loci in 32 Engelmann spruce trees and for seven polymorphic loci in 40 subalpine fir trees. The Gdh and Idh loci in spruce were very tightly linked: no recombinants were detected among 60 megagametophytes of trees heterozygous for both loci. In fir only the Aco and Pgm-1 loci were linked, with an estimated recombination rate of 0.317 ± 0.073. The low levels of among-tree heterogeneity and of segregation distortion found in these populations suggest that reliable estimates of both genetic variation and outcrossing rates can be obtained using allozyme data from these wind-pollinated species.Key words: segregation, linkage, allozymes, Engelmann spruce, subalpine fir.

Inonotus tomentosus and the dynamics of unmanaged and partial-cut wet sub-boreal spruce–fir forests

2007 ◽  
Vol 37 (12) ◽  
pp. 2663-2676 ◽  
Author(s):  
J. E. (Ted) Newbery ◽  
Kathy J. Lewis ◽  
Michael B. Walters
Keyword(s):  
Picea Glauca ◽  
Dead Wood ◽  
Basal Area ◽  
Tree Density ◽  
Small Scale ◽  
Abies Lasiocarpa ◽  
Partial Cutting ◽  
Subalpine Fir ◽  
Engelmann Spruce ◽  
Live Tree

For wet sub-boreal spruce–fir forests (white spruce ( Picea glauca (Moench) Voss) × Engelmann spruce ( Picea engelmannii Parry ex Engelm.) – subalpine fir ( Abies lasiocarpa (Hook.) Nutt.)) in east-central British Columbia, we asked (i) do compositional and structural dynamics differ for unmanaged (UN) and partial-cut (PC) (50% removal 45 years before measurement) forests and (ii) how does Inonotus tomentosus Fr. (Teng) affect these dynamics? Inonotus tomentosus infected stands had 17% less spruce basal area (P = 0.059) than uninfected stands, but PC did not exacerbate I. tomentosus effects. PC and UN had similar live tree density, but UN had lower dead tree density. In all stands, snag longevity was typically <32 years, and ~40 years was required for dead wood to reach decay stage 3 or greater. UN was characterized by variable severity disturbances averaging ~8% of the canopy per decade. Management implications include the following: (i) harvest systems designed to emulate small-scale disturbance could remove trees at 8% of the canopy per decade, varied spatiotemporally, (ii) emulating dead wood abundance with partial cutting may be difficult given the impacts of partial cutting on dead wood abundance, and (iii) forests with moderate levels of I. tomentosus should not respond differently to harvesting than uninfected forests and thus require no special management.

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