Genetic gains from 20 years of cooperative tree improvement in New Brunswick

2004 ◽  
Vol 80 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Bryce McInnis ◽  
Kathleen Tosh

The New Brunswick Tree Improvement Council analyzed 20-year data from plantations of unimproved and first generation improved black spruce (Picea mariana [Mill.] BSP) and jack pine (Pinus banksiana Lamb.). STAMAN, a computer model, conservatively projected an 11% merchantable volume gain at 40 years based on 20-year measurements of 36 000 trees. At age 20 years, first generation black spruce was 12% taller and 25–30% greater in total volume. Projections from over 160 000 individual measurements of height from age five to 20 years indicate that by 40 years, gains of 7–8% in height and 18–20% in total volume are likely. Ten year assessments from over 10 000 measurements of second generation black spruce indicate a 30% height gain over first generation material of the same age. For jack pine first generation material, the projections indicated a height gain of 14% and a total volume gain of over 30% at 40 years. Faster growth can provide greater volume at rotation age, a shorter rotation interval, or earlier interventions for commercial thinning. Key words: genetic gain, tree improvement, black spruce, jack pine

2009 ◽  
Vol 85 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Xiangdong Lei ◽  
Changhui Peng ◽  
Haiyan Wang ◽  
Xiaolu Zhou

Historically, height–diameter models have mainly been developed for mature trees; consequently, few height–diameter models have been calibrated for young forest stands. In order to develop equations predicting the height of trees with small diameters, 46 individual height–diameter models were fitted and tested in young black spruce (Picea mariana) and jack pine (Pinus banksiana) plantations between the ages of 4 to 8 years, measured from 182 plots in New Brunswick, Canada. The models were divided into 2 groups: a diameter group and a second group applying both diameter and additional stand- or tree-level variables (composite models). There was little difference in predicting tree height among the former models (Group I) while the latter models (Group II) generally provided better prediction. Based on goodness of fit (R2and MSE), prediction ability (the bias and its associated prediction and tolerance intervals in absolute and relative terms), and ease of application, 2 Group II models were recommended for predicting individual tree heights within young black spruce and jack pine forest stands. Mean stand height was required for application of these models. The resultant tolerance intervals indicated that most errors (95%) associated with height predictions would be within the following limits (a 95% confidence level): [-0.54 m, 0.54 m] or [-14.7%, 15.9%] for black spruce and [-0.77 m, 0.77 m] or [-17.1%, 18.6%] for jack pine. The recommended models are statistically reliable for growth and yield applications, regeneration assessment and management planning. Key words: composite model, linear model, model calibration, model validation, prediction interval, tolerance interval


1998 ◽  
Vol 78 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Helmut Krause

The purpose of this study was to determine whether change of forest cover had an effect on the development of the organic surface horizons, particularly on those variables that influence nutrient cycling and forest productivity. Jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.) plantations were selected from among the youngest to oldest (2–16 yr) within a 100 km2 area in southeastern New Brunswick. Natural forests were also included as benchmark sites. The forest floor and tree foliage was sampled and trees measured on 0.05-ha plots. The forest floor samples were used to determine organic mass, nutrient contents and pH. In pine plantations, organic matter accumulated rapidly during the period of exponential tree growth, but leveled off at about 45 Mg ha–1. This was within the range of benchmark sites with mixed conifer-hardwood cover. In spruce plantations, the forest floor mass ranged upward to 77 Mg ha–1. Development was strongly influenced by the nature of the previous forest. Spruce forest floors were on average more acid and had lower nutrient concentrations, particularly N and Ca. The observed differences suggest that nutrients are recycled more rapidly in the pine plantations, partly explaining the superior growth of the latter. Key words: Forest floor, Kalmia angustifolia L., Picea mariana (Mill.) B.S.P., Pinus banksiana Lamb., nutrient cycling, plantation forest


2004 ◽  
Vol 34 (9) ◽  
pp. 1938-1945 ◽  
Author(s):  
Isobel Waters ◽  
Steven W Kembel ◽  
Jean-François Gingras ◽  
Jennifer M Shay

This study compares the effects of full-tree versus cut-to-length forest harvesting methods on tree regeneration in jack pine (Pinus banksiana Lamb.), mixedwood (Picea glauca (Moench) Voss – Populus tremuloides Michx. – Abies balsamea (L.) Mill.), and black spruce (Picea mariana (Mill.) BSP) sites in southeastern Manitoba, Canada. We surveyed tree regeneration densities, disturbance characteristics, and understorey vegetation in replicated control and harvested plots in each site type preharvest (1993) and 1 and 3 years postharvest (1994, 1996). In jack pine sites, the full-tree harvest method promoted regeneration of Pinus banksiana through increased disturbance of soil and the moss layer, and decreased slash deposition relative to the cut-to-length method. Conversely, in mixedwood sites the cut-to-length method resulted in less damage to advance regeneration and proved better at promoting postharvest regeneration of Abies balsamea and Picea glauca relative to the full-tree method. In black spruce sites, there were few differences in the impact of the two harvesting methods on regeneration of Picea mariana, which increased in frequency and density after both types of harvesting.


1975 ◽  
Vol 51 (2) ◽  
pp. 53-54
Author(s):  
W. Stanek

Black spruce (Picea mariana [Mill.] B.S.P.) and jack pine (Pinus banksiana Lamb.) seedlings were grown in a green-house on peat-filled flats flooded with nutrient solution or distilled water. None was aerated. However, an O2 concentration gradient existed across the flats, 3.0 – 3.7 ppm along the edges, and 1.4 – 1.9 ppm in the centers. After 4½ months seedlings of both species grew taller with nutrient solution than with distilled water. In flats supplied with nutrient solution, seedlings of both species grew taller along the edges than in the centers, whereas in flats supplied with distilled water height differential did not develop. Jack pine grew taller than black spruce under similar conditions.


1986 ◽  
Vol 62 (5) ◽  
pp. 446-450 ◽  
Author(s):  
S. W. J. Dominy ◽  
J. E. Wood

Seeding trials were established on four different sites in northern Ontario (46°41′N to 49°19′N) in 1979 and 1980. Jack pine (Pinus banksiana Lamb.) was seeded on two medium sand sites, black spruce (Picea mariana [Mill.] B.S.P.) on a sandy clay site, and white spruce (P. glauca [Moench] Voss) on a clay site. Conventional bare spot seeding was compared with spot seeding under Finnish-designed plastic shelters. At least two seeding dates were compared in each trial. Third- and fifth-year stocking and fifth-year height data are presented.Stocking of all three species was increased, regardless of sowing date, when shelters were used. With the exception of June-sown black spruce and one June sowing of jack pine, height growth was not significantly improved through the use of seed shelters. Shelters may prove to be a viable regeneration option only on cooler, exposed sites with little vegetative competition. Key words: Shelter spot seeding, bare spot seeding, Pinus banksiana Lamb., Picea mariana [Mill.] B.S.P., P. glauca [Moench] Voss.


2010 ◽  
Vol 86 (2) ◽  
pp. 193-199 ◽  
Author(s):  
G. Geoff Wang ◽  
Kevin J Kemball

Two boreal mixedwood stands burned by the 1999 Black River wildfire in southeastern Manitoba, Canada were selected to study the effect of fire severity on early survival and growth of planted jack pine (Pinus banksiana), black spruce (Picea mariana) and white spruce (Picea glauca) seedlings. In each stand, three fire severity classes (scorched, lightly burned, and severely burned) were identified based on the degree of forest floor consumption. Fire severity was not a significant factor on mortality. No mortality difference was found among species, except for year 5 when jack pine had significantly higher mortality than both black spruce and white spruce. Jack pine and black spruce had their highest mortality in year 4, while white spruce had its highest mortality in year 1. Under natural competition, seedling growth increased with increasing fire severity. When competition was removed, fire severity did not affect seedling growth. Regardless of fire severity and competition, jack pine had better diameter and height growth than black spruce, which, in turn, grew slightly taller than white spruce. Planted seedlings faced less intense vegetation competition on severely burned plots compared to scorched or lightly burned plots. Regardless of fire severity and species, competition increased with time since planting. Our study results indicate that planting immediately after a wildfire is a viable option to establish conifer components on burned boreal mixedwood stands. Key words: fire severity, plantation, regeneration, Pinus banksiana, Picea mariana, Picea glauca


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