Postfire environmental conditions influence the spatial pattern of regeneration for Pinus ponderosa

2005 ◽  
Vol 35 (1) ◽  
pp. 37-47 ◽  
Author(s):  
V H Bonnet ◽  
A W Schoettle ◽  
W D Shepperd

Regeneration of ponderosa pine after fire depends on the patterns of seed availability and the environmental conditions that define safe sites for seedling establishment. A transect approach was applied in 2002 to determine the spatial distribution of regeneration from unburned to burned areas within the landscape impacted by the Jasper Fire of 2000 in the Black Hills of South Dakota (USA). Canopy conditions alone, reflecting seed availability, at the stand level were not correlated with regeneration success. However, canopy conditions in combination with ground conditions explained patterns of regeneration success at the plot level (2 m × 6 m scale), and ground conditions explained these patterns at the quadrat level (0.2 m × 0.2 m scale). Only at the finer level of the quadrat could environmental factors explain seedling survival. Safe sites were characterized, in part, by the presence of scorched needle litter on blackened mineral soil. Areas with high understory cover restricted regeneration in the undisturbed forest and reduced seedling survival in the burned areas. The description of environmental conditions that favor and discourage ponderosa pine regeneration success will improve our understanding of how environmental heterogeneity within burned areas will contribute to the future forested landscape.

2020 ◽  
Vol 50 (9) ◽  
pp. 862-871 ◽  
Author(s):  
Thomas E. Kolb ◽  
Kelsey Flathers ◽  
John B. Bradford ◽  
Caitlin Andrews ◽  
Lance A. Asherin ◽  
...  

Trees in dry forests often regenerate in episodic pulses when wet periods coincide with ample seed production. Factors leading to success or failure of regeneration pulses are poorly understood. We investigated the impacts of stand thinning on survival and growth of the 2013 cohort of ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) seedlings in northern Arizona, United States. We measured seedling survival and growth over the first five growing seasons after germination in six stand basal areas (BAs; 0, 7, 14, 23, 34, and 66 (unthinned) m2·ha−1) produced by long-term experimental thinnings. Five-year survival averaged 2.5% and varied among BAs. Mean survival duration was longer in intermediate BAs (11 to 16 months) than in clearings and high BAs (5 months). The BAs of 7, 14, and 23 m2·ha−1 had >2600 5-year-old seedlings·ha−1. In contrast, regeneration was lower in the clearing (666 seedlings·ha−1) and failed completely in the 34 m2·ha−1 and unthinned treatments. Seedling survival was highest during wet years and lowest during drought years. Many surviving seedlings had no net height growth between years 4 and 5 because of stem browsing. Results indicate that natural regeneration of ponderosa pine is influenced by stand BA, drought, herbivory, and interactions between extreme climatic events.


2003 ◽  
Vol 18 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Steven J. Stein ◽  
Diana N. Kimberling

Abstract Information on the mortality factors affecting naturally seeded conifer seedlings is becoming increasingly important to forest managers for both economic and ecological reasons. Mortality factors affecting ponderosa pine (Pinus ponderosa) seedlings immediately following natural germination and through the following year were monitored in Northern Arizona. The four major mortality factors in temporal order included the failure of roots to establish in the soil (27%), herbivory by lepidopteran larvae (28%), desiccation (30%), and winterkill (10%). These mortality factors were compared among seedlings germinating in three different overstory densities and an experimental water treatment. Seedlings that were experimentally watered experienced greater mortality than natural seedlings due to herbivory (40%), nearly as much mortality due to the failure of roots to establish in the soil (20%), less mortality due to winterkill (5%), and no mortality due to desiccation. The seedling mortality data through time were summarized using survivorship curves and life tables. Our results suggest that managers should consider using prescribed burns to decrease the percentage of seedlings that die from failure of their roots to reach mineral soil and from attack by lepidopteran larvae. West. J. Appl. For. 18(2):109–114.


1991 ◽  
Vol 67 (3) ◽  
pp. 245-248 ◽  
Author(s):  
J. L. Kingery ◽  
R. T. Graham

During the summer and fall of 1982, a study was established on the Nez Percé National Forest in central Idaho to assess the effects of cattle grazing on the performance of a new ponderosa pine (Pinus ponderosa Laws.) plantation. Three study sites were located in a Douglas-fir/ninebark (Pseudotsuga menziesii/Physocarpus malvaceus) habitat type. Results after six years showed that livestock use can influence tree seedling establishment. Mortality and damage to tree seedlings from cattle resulted primarily from trampling rather than from browsing. Five and one-half percent of the seedlings were damaged by cattle, of which 3.6% died. Browsing by deer and elk caused the most growth loss. Overall damage was greatest from non-animal causes. Seedling quality at the time of planting, handling of the seedling, and droughty conditions during the first two years of the study contributed to this type of damage. Overall performance of the tree seedlings were relatively poor. Total mortality to tree seedlings resulting from all sources of damage was 43.6% for the grazed treatment and 25.3% for the non-grazed treatment.


2002 ◽  
Vol 17 (3) ◽  
pp. 117-121 ◽  
Author(s):  
David L. Wenny ◽  
Daniel J. Swanson ◽  
R. Kasten Dumroese

Abstract Ponderosa pine (Pinus ponderosa) seedlings from Idaho (var. ponderosa) and Arizona (var. scopulorum) grown in a container nursery received optimum chilling [2,010 hr (84 days) of temperatures below 5°C]. While seedlings were in the greenhouse, days required for 50% of the population to break bud were similar for both seed sources and decreased inverse exponentially from 74 to 23 days as chilling hours accumulated to the optimum. When subsequently placed into either refrigerated or frozen storage, Idaho seedlings broke bud significantly faster than Arizona seedlings when returned to favorable environmental conditions for growth. All seedlings removed from refrigerated storage broke bud faster, were less cold tolerant, and therefore less quiescent than seedlings that had been frozen. West. J. Appl. For. 17(3):117–121.


2013 ◽  
Vol 43 (6) ◽  
pp. 570-583 ◽  
Author(s):  
Melissa Savage ◽  
Joy Nystrom Mast ◽  
Johannes J. Feddema

We examine regeneration dynamics across landscapes under extreme climate conditions and a human-altered fire regime in ponderosa pine (Pinus ponderosa Douglas ex Lawson & C. Lawson) forests of the American Southwest. Our research asks how well these forests recover when unprecedented conditions of a high-severity fire regime combine with historical drought conditions. Tree recruitment is documented at five sites in New Mexico after high-severity fires that burned forests in the drought that prevailed from ∼1945 to 1958. We develop a water-balance type model to evaluate how altered microclimate conditions in the years after a fire and during a drought may inhibit ponderosa pine regeneration in comparison with drought conditions alone. We empirically identify two pathways of forest recovery following high-severity fires during drought: recovery to nonforest types, either dense shrubfields or shrubs in grasslands (four sites) or recovery to hyperdense forest (one site). Model simulations predict fewer favorable opportunities for germination, fewer periods favorable for seedling establishment, shortening of favorable establishment periods, and more adverse conditions because of later spring and earlier fall hard freezes. Our research suggests that a specific climate window critical to the capacity of southwestern ponderosa pine trees to regenerate is narrowed by a synchronous occurrence of high-severity fire and drought.


1984 ◽  
Vol 62 (1) ◽  
pp. 44-52 ◽  
Author(s):  
David W. Pratt ◽  
R. Alan Black ◽  
B. A. Zamora

The seed bank of a Pinus ponderosa – Symphoricarpos albus stand in east-central Washington was examined with respect to species composition, depth distribution, and germination responses to heat and shade treatments. Seeds of 57 species were present in the seed bank to a depth of 10 cm. Twenty-one of these species were not found in the aboveground vegetation of the study area. Estimated viable seed densities in spring and autumn collections were 13 052 ± 1481 and 14 463 ± 1356 seeds m−2, respectively. Stellaria media and Poa pratensis, both alien species, accounted for 50% of the buried viable seed. Seed density was highest in litter samples. Total seed density decreased with soil depth, although seeds of some pioneer species were more abundant in the mineral soil than in the litter. Species dominating the seed bank were generally unimportant in the aboveground vegetation. Woody species, which dominated the aboveground vegetation, accounted for only 1% of the seed bank. Annual forbs dominated the seed bank (45% of total buried viable seed) but were not dominant in the vegetation. Seeds of several species survived prestratification heat treatments. Poststratification heat treatments inhibited germination or destroyed seed of nearly all species. As shading increased, germination of most species decreased. However, shade did not inhibit germination of species characteristic of mature successional stages.


2009 ◽  
Vol 24 (3) ◽  
pp. 151-156
Author(s):  
Amanda Lindsay ◽  
Paul Oester ◽  
Elizabeth Cole

Abstract Chemical control of competing vegetation with hexazinone is a common and effective silvicultural treatment for ensuring ponderosa pine (Pinus ponderosa Laws.) plantation success on dry sites in the western United States, yet few studies document the effect for more than the first few years after planting. This study, re-evaluated 20 years after planting, followed ponderosa pine growth and survival when hexazinone was applied in broadcast and spot treatments for control of competing vegetation. We continued work from the first 5 years after establishment that identified early differences in ponderosa pine seedling survival and growth with treatment. Examination of 20-year trends indicated that individual tree volume and volume per hectare continued to diverge among treatments. The economic differences among treatments may increase as more surviving, faster-growing trees in the broadcast treatments reach higher-value products sooner. Initial control of competing vegetation increased the likelihood of seedling survival and increased tree size after 20 years. Results pertained to ponderosa pine of the Douglas-fir/spiraea (Pseudotsuga menziesii var. glauca Beissn./Spiraea betulifolia Pall.) and Douglas-fir/common snowberry (Pseudotsuga menziesii var. glauca Beissn./Symphoricarpos albus [L.] S. F. Blake) plant associations in northeastern Oregon, but they should apply to similar sites throughout much of the intermountain West.


1991 ◽  
Vol 6 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Robin Rose ◽  
John Gleason ◽  
Mary Atkinson ◽  
Tom Sabin

Abstract In probably one of the first studies of its kind, three different seed sources of 2 + 0 ponderosa pine (Pinus ponderosa) seedlings were graded on the basis of three root-volume categories (< 4.5, 4.5-7, and > 7 cm³) and out-planted to determine differences in survival and growth over 1 and 2 growing seasons, examine the relationship of seedling field height to nursery root volume, total fresh weight, diameter, and height over the same period, and observe differences in nutrient uptake by seedlings among the three categories over 174 days in the field. Seedling survival was good over the two growing seasons. Seedlings graded to the largest root-volume category were significantly taller and grew significantly more than those in the two smaller categories over the 2 years. Nitrogen and potassium contents decreased over the growing season, those seedlings with larger root volumes showing the greatest decrease. The results suggest that root volume has potential as a useful criterion for grading seedlings. West. J. Appl. For. 6(1):11-15.


2004 ◽  
Vol 13 (2) ◽  
pp. 183 ◽  
Author(s):  
Angela D. Barclay ◽  
Julio L. Betancourt ◽  
Craig D. Allen

Forty-nine vegetation transects were measured in 1997 and 1998 to determine the impact of grass seeding after the 1996 Dome Fire, which burned almost 6900 ha of ponderosa pine (Pinus ponderosa Lawson) forest in the Jemez Mountains of north-central New Mexico. High- and moderate-burned areas in Santa Fe National Forest were seeded with a mixture that included the exotic ryegrass (Lolium multiflorum Lam.). Adjacent burned areas of Bandelier National Monument were not seeded, and were used as a control in the post-seeding study. On the seeded plots, foliar cover of ryegrass declined from 1997 to 1998 due to self-inhibition and/or reduced precipitation from 1997 to 1998. Foliar cover and diversity of native forbs were greater in 1997 than 1998, probably due to a wet growing season in 1997. Cover, species richness, and diversity of native forbs were highest in non-seeded areas of moderate- and high-burn intensities. Regeneration and survivorship of conifer seedlings decreased as ryegrass cover increased, particularly in areas of high-burn intensity. Exotic plant cover, mostly horseweed [Conyza canadensis (L.) Cronq.], increased from 1997 to 1998 in non-seeded areas of moderate- and high-burn intensity. Both the initial success of seeding and the eventual impacts on native vegetation were strongly modulated by climate variability.


Author(s):  
Д.В. Гусев

Естественное возобновление является важным фактором формирования насаждений, особенно главных лесообразующих пород. Растительное сообщество становится жизнестойким при условии способности восстановить численность популяций заменой погибших экземпляров новыми. Было выяснено в каком количестве происходит естественное возобновление сосны на гарях по сравнению с граничащими участками, не пройденными пожарами, взятые в качестве контроля. Район исследований относится к южной подзоне тайги на территории Ленинградской области в Кировском и Лужском лесничествах. Объектом исследований стали сосновые насаждения, где работы проводились в летний период с 2013 по 2015 год. Всего подобрано 36 участков (включая контроль) размером не более 0,3 га. Учет подроста проводился на учетных площадках. Каждая учетная площадка закладывалась при помощи шеста длиной 178,5 см. Площадь круговых площадок составляла 10 м2, они расположены последовательно друг за другом с непосредственным примыканием. На каждой площадке проводили перечет подроста и делили его по высоте на три категории крупности: мелкий до 0,5 м, средний – 0,6–1,5 м и крупный – более 1,5 м. А также естественное возобновление на участках делили по густоте – на три категории: редкий – до 2 тыс., средней густоты – 2–8 тыс., густой – более 8 тыс. растений на 1 га; по распределению по площади – на три категории в зависимости от встречаемости. Анализ послепожарного возобновления в сосняках показал, что на пробных площадях наблюдается отличное возобновление подроста сосны и обилие на площади, все это связано с уничтожением лесной подстилки, увеличением минерализации почвы что, в конечном счете, положительно влияет на естественное лесовосстановление, о чем свидетельствует появление всходов, а также лучше становится гидрологический режим почвы. Благодаря этому происходит хорошее восстановление. Количество благонадежного подроста составляет от 3,5 до 11,9 тыс. шт./га и его достаточно для естественного восстановления ценопопуляции после пожара. Подтверждена зависимость количество самосева и толщины лесной подстилки. Прогретая после пожара, богатая минеральными веществами почва благоприятна для появления всходов и самосева древесных растений. Natural regeneration is an important factor in the formation of plantations, especially the main forest-forming species. Plant community becomes viable, provided the ability to recover populations, replacement of lost copies new. Find out how much happens in a natural pine regeneration in burned areas compared to adjacent areas not affected by fires, are taken as a control. The study area belongs to the subzone of southern taiga on the territory of Leningrad region, the Kirov and Luga districts. The object of research became pine plantations where the work was carried out in year period from 2013 to 2015. Just picked up 36 stations (including the control) no larger than 0.3 hectares. accounting for the undergrowth was conducted on index sites. Each user platform was laid with a pole length of 178.5 cm the area of the circular pads was 10 m2, they are located successively one after another with a direct connection. At each site conducted the translation of the undergrowth and it was divided in height into three categories of size: small up to 0.5 m, average 0.6 to 1.5 meters and large – more than 1.5 meters. And natural regeneration on plots divided by the density for three categories: rare – up to 2 thousand, medium density – 2 to 8 thousand, thick – more than 8 thousand plants per 1 ha; on the distribution of the area – into three categories depending on the occurrence. Analysis of post-fire regeneration in pine forests showed that the sample areas there is a great renewal of undergrowth of pine and the abundance on the square, all this is due to the destruction of forest litter, increasing salinity of the soil which, ultimately, has a positive effect on natural regeneration, as evidenced by the appearance of seedlings, as well as better hydrological regime of the soil. Which a good recovery. The number of reliable undergrowth is from 3.5 to 11.9 thousand PCs/ha, enough for natural regeneration of seedlings after the fire. Confirmed the dependence of the number of self-seeding and thickness of forest litter. After the fire-warmed, mineral-rich soil is favorable for emergence and self-seeding of woody plants.


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