Wildfire is a natural phenomenon in Canada that threatens to destroy property and endanger lives. Wildfire agencies are tasked with reducing the threat of wildfire in the wildland-urban interface, which becomes a greater issue as more communities locate near or within forests or become more populated.
Forest fuel treatments that reduce or modify forest stands are the most common and effective methods to reduce wildfire danger around communities. However, convincing the public to support forest fuel treatments around their communities can be a challenge for wildfire managers. Understandably, communities want some assurance that what they are committing to will make a difference. One of the many benefits of forest fuel treatments is thought to be an increase in the effectiveness of wildfire operations.
This report summarizes work that was performed at the request of Quebec’s Ministère des Ressources Naturelles et de la Faune (MRNFQ) as part of updating their economic models for hardwood forest. The study compared the productivity of mechanized felling in a selection cut with the productivity of the same equipment and operators working in a regeneration cut. This comparison generated regression equations for the productivity of mechanized felling as a function of mean stem volume for each type of cut in hardwood and mixed forests.
In a previously completed study, lumber obtained from a 95-year old lodgepole pine sample representing a final stand density of 700 live stems/hectare (s/ha) was found to have relatively low modulus- of-rupture (MOR) and modulus of elasticity (MOE). It was determined that this resulted from lower than average basic wood density, and larger than average knot size particularly in large diameter trees. It was also determined that average MOR and MOE could be predicted to some extent (R2 > .60) on the basis of tree diameter-at-breast height (d.b.h.) and breast-height average basic wood density. Before accepting the above results as typical of lodgepole pine of similar age and final stand density, it was considered important to compare the relationships between d.b.h. and breast-height wood density observed in this 700 s/ha sample with that of trees in open-stand-densities in other regions. Average branch size added only marginally to explained variation in the predictive equation, but knot size is known to effect lumber strength. Thus a measure of branch size was included in the current study plan. Biogeoclimatic zones were chosen as the basis for regional comparisons. A minimum of 30 trees were selected from open-stand sites in each of the following five biogeoclimatic zones: Montane Spruce (MS), Engelmann Spruce-Subalpine Fir (ESSF), Interior Douglas-Fir (IDF), Interior Cedar-Hemlock (ICH) and Sub-Boreal Spruce (SBS). Sampling was systematic by d.b.h. to ensure representation of small, medium and large diameter trees. Stem counts were made in 1/200 ha plots around each sample tree to ensure that samples were indicative of a relatively open stand density. Average basic wood density at breast height was determined from two pith-to-bark increment cores obtained from each sample tree. The size and height of the largest branch in the first 5 m of tree height was measured and recorded. Average basic wood density values and estimates of branch size obtained for the five samples in this study were compared to the values and estimates obtained from the original 700 s/ha sample site. Basic wood density obtained from three of the sites was not significantly different from that of the 700 s/ha sample. It was significantly higher in one site (ICH) and significantly lower in another (ESSF). The higher wood density was possibly the result of a slower growth rate to 30 years combined with older average tree age. The significantly lower wood density was attributed to a younger average stand age (80 years). Basic wood density showed a consistent relationship with d.b.h. in all of the tree samples, tending down as d.b.h. increased. There was a less consistent relationship between knot size and d.b.h. but what relationship there was would serve to reinforce the effect of differences in wood density on lumber strength and stiffness. Average size of the largest knots was smallest in the tree sample where wood density was highest, and largest in the sample where wood density was lowest. Important lumber strength determining tree characteristics (wood density and knot size) that resulted in the low MOE and MOR at the original 700 s/ha sample site were found to be unexceptional when compared to trees of similar age and final stand densities in other biogeoclimatic zones. Although a slower than average growth rate to 30 years offers a plausible explanation for the higher than expected wood density in the ICH sample, further investigation is recommended.
Au Québec, l’intervention de récolte forestière la plus répandue en forêt résineuse est la coupe avec protection de la régénération et des sols (CPRS). Cette intervention consiste à récolter toutes les tiges marchandes (10 cm et plus au DHP) tout en protégeant la régénération préétablie et les sols. Pour ce faire, la machinerie forestière se restreint à emprunter des sentiers espacés de manière à limiter les superficies perturbées.
Dans les peuplements à structure irrégulière ou étagée, la CPRS n’est pas toujours le traitement le plus approprié. Ces peuplements sont composés d’une portion variable de tiges ayant un diamètre à hauteur de poitrine (DHP) de 10 à 12 cm qui pourrait contribuer de manière significative au volume d’un peuplement futur. Ces petites tiges sont dispendieuses à récolter, elles diminuent le rendement en bois de sciage et elles ont peu d’influence sur le volume total récolté. Pour aménager adéquatement les peuplements à structure irrégulière ou étagée, la coupe avec protection des petites tiges marchandes (CPPTM) a été développée. La CPPTM ressemble à la CPRS, à l’exception que les tiges de 10 et 12 cm (parfois jusqu’à 16 cm) sont protégées. Ce traitement est actuellement pratiqué dans plusieurs régions et sera ajouté à la 4e édition du Manuel d’aménagement forestier. Le présent document traite de l’approche opérationnelle de la CPPTM avec la machinerie forestière utilisée au Québec.
FERIC monitored a prototype machine designed to perform simultaneous crushing and scarification for the treatment of burned sites. The prototype was productive, but couldn't always produce an adequate number of plantable microsites, particularly on sites with thick humus.
FERIC's study examined the potential of intensive site preparation based on a double treatment (brushcutting plus harrowing) as an alternative to expensive mulching techniques for stand conversion. Although the proposed technique did not work the soil as completely as mulching, it significantly decreased treatment costs.
In 1996 FERIC studied commercial thinning on seven operating areas in Alberta in order to quantify the effect of tree size and stand density on harvester and forwarder productivities. As well, the cost of harvester and forwarder operations was determined and slash loading and damage to residual trees were measured.
The study objective was to determine if differences in the quality of Douglas-fir in the B.C. Interior could be assessed on the basis of characteristics visible in standing trees so as to provide site-specific measures of stand value. Six sawmill studies, with a final sample of 1,862 trees are described. Sample trees were selected and their quality characteristics recorded. These trees were felled and their logs processed into finished lumber from which individual tree values were calculated. An index shows the effect of tree quality and tree size on average lumber value per unit volume. A description of each mill study allows comparison of average sound lumber recovery factors.
This study examined the impact of pre-commercial thinning (PCT) on tree growth, product recovery, stand value and financial return in jack pine stands in Northern Ontario. This study was based on 10 sites composed of both control and thinned stands, and the sites represent various stand densities and stand ages. In each site, 5 circular plots of 5.64 m in radius were randomly selected from each of the control and thinned stands. In each plot, all trees were measured for tree DBH and total tree height. A total of 3118 trees were measured from the 100 plots within the 10 sites. These measurements were used to estimate tree volume, merchantable stem volume, and product recovery. Tree or stem volume were estimated using a general volume equation developed by the Canadian Forest Service in Fredericton, while lumber volume and value recovery from each tree were assessed using models for describing the relationship of lumber recovery to jack pine tree characteristics (DBH and tree height) developed by Forintek. Both dimension and stud mills were considered for the product recovery. Sawdust was assumed to be 5% of the merchantable stem volume, whilst volume of the chips from each tree was calculated by subtracting lumber and sawdust volume from the merchantable stem volume.
PCT treatment in jack pine has a positive effect on both diameter and tree height growth of individual trees. Average diameter of trees from thinned stands was larger than for those from control stands for all 10 sites, and a similar trend was noticed for total tree height.
When stand density ranged from 2,000 to 3,000 trees/ha, average DBH in the control stands tended to decrease moderately with increasing stand density, however, when stand density increased to between 3000 and 6000 trees/ha, average DBH appeared to decrease slowly. With increasing stand density, no consistent pattern could be recognized for the DBH of the thinned stands. However, the magnitude of the increment in average DBH due to PCT increases with increasing thinning intensity.
PCT treatment accelerates tree diameter and height growth of individual trees, but it generally reduces total tree volume and merchantable stem volume per hectare due to the reduced number of trees. Thanks to a considerably higher lumber volume recovery per m3 associated with larger tree diameter, however, the total lumber volume and value recovery per hectare in the thinned stands are still improved. Compared to the control stands, the thinned stands on average produced 6.92 Mfbm (18%) or $2658.92 (20%) (from the dimension mill) and 3.86 Mfbm (22%) or $1783.68 (29%) (from the stud mill) more lumber per hectare. In contrast, the control stands produced 24.4 m3 or $1,142 (39.5%) (from the dimension mill) and 17.7 m3 or $828 (16.6%) (from the stud mill) more chip recovery per hectare.
PCT has a positive effect on total product value recovery. About half of the 10 stands receiving PCT had a higher total product value (from $1850 to $7147 per hectare for the dimension mill and from $3698 to $6634 per hectare for the stud mill, respectively) than the control stands, while the rest of the thinned stands produced lower total values than the control stands. On average, the thinned stands produced approximately $1,500 and $960 (or 9.9% and 8.6%) more product value per hectare for the dimension mill and stud mill, respectively.
PCT also has a positive effect on logging and lumber conversion costs thanks to a larger tree diameter. As a result, the total costs for the thinned stands including the PCT treatment cost, interest charges, stumpage fee, costs for harvesting, transportation and lumber conversion were lower than those for the control stands. Therefore, the thinned stands had a higher ratio of benefits/costs.
Overall, this study indicates that PCT appears to be an economically viable silvicultural investment for jack pine stands in Northwestern Ontario.
Most companies that harvest softwoods will eventually implement commercial thinning operations. This report covers the many considerations required to develop the expertise to manage such operations, and examines the most important aspects of this management. Although not all strategies discussed in this report have been the subject of extensive research, they nonetheles represent a pooling of the experience of those companies at the forefront of thinning in the eastern Canada. The report discusses the characteristics of the wood produced by thinning, stand selection, the characteristics of suitable stands, homogeneity of the forest cover, the road infrastructure, inventories, and the logistics required for quality control. The report concludes with a summary of suitable harvesting systems.