Hibiscus elatus (blue mahoe).

The Caribbean tree H. elatus, known as blue mahoe or majagua, is a highly valued, fast-growing timber species that has adapted to a wide range of sites and is often used in reforestation. It produces excellent timber for high-grade furniture, but can also be used as a windbreak. Ease of germination results in successful plantation establishment. It could be grown on a larger scale as a plantation crop but suffers from epicormic branching and sweep. H. elatus is also grown for ornamental and shade purposes and is the national tree of Jamaica.

Response of ice-damaged northern hardwood stands in northern New York

At three previously thinned, even-aged northern hardwood stands affected by the 1998 ice storm, we evaluated the responses of trees in plots given a rehabilitation treatment, and compared findings to adjacent untreated areas. In both the rehabilitated and untreated areas mortality seemed consistent with regional norms for northern hardwood stands. Trees that died after the storm had essentially complete crown loss due to ice loading, and 12% of living trees lost at least half of their crown. In both sets of plots, epicormic branching within the crown led to crown rebuilding, resulting in high levels of tree survival and good post-storm diameter growth on all plots. Release of selected upper-canopy trees by the rehabilitation cutting significantly increased diameter growth rates compared to those in untreated areas. While some epicormics developed below the base of the original crown in both treated and untreated plots, they largely emanated at > 5.2 m from the ground and did not degrade the butt log of most trees.

Viability of Northern Pin and White Oak Reserve Trees in Wisconsin Scrub Oak Sites

Retention of reserve trees can serve multiple objectives when harvests are conducted on scrub oak sites. The objective of the study was to determine the growth and vigor response of northern pin and white oak held as reserve trees from harvests occurring over a 15-year time period onscrub oak sites in Central Wisconsin. Reserve trees were evaluated for volume growth, epicormic branching, live crown ratio, and tree vigor. White oak maintained or improved in vigor and exhibited increased rates of volume growth with no measured mortality. Northern pin oak, although exhibitingincreased volume growth, tended to decline in vigor and experienced an overall annual mortality rate of 5.5%. For managers that are considering multiple objectives, white oak can provide a long-lived vigorous reserve tree while northern pin oak may survive but will experience decline and higherrates of mortality, which may contribute to a long-term goal of snag retention as an element of wildlife habitat.

Post-fire epicormic branching in Sierra Nevada Abies concolor (white fir)

In California’s mixed-conifer forest, which historically had a regime of frequent fires, two conifers, Sequoiadendron giganteum and Pseudotsuga menziesii, were previously known to produce epicormic sprouts from branches. We found epicormic branching in a third mixed-conifer species, Abies concolor, 3 and 4 years after a wildfire in the central Sierra Nevada Mountains of California. Sprouting occurred only from the boles. We investigated (1) whether the degree of crown loss and the extent of epicormic branching were independent; and (2) whether epicormic branching differed by tree size. The vertical extent of epicormic foliage increased with increasing severity of crown loss. There was a significantly greater proportion of large diameter-class (>50 cm diameter at breast height [dbh]) trees with epicormic branching than small/medium diameter-class (25–50 cm dbh) trees. These results suggest large diameter Abies concolor may survive high levels of crown loss, aided by crown replacement through epicormic branching, but that reiterative green foliage may not appear for up to 3 years after fire damage. If this response is widespread, it would suggest some ‘dying’ trees logged under current salvage guidelines could survive, and that higher-intensity fire may substantially reduce the density of small post-fire suppression white fir, while retaining many larger overstory trees.

Conifer response to three silvicultural treatments in the Oregon Coast Range foothills

This study assessed growth, condition, and mortality of residual trees one decade after harvest across three silvicultural treatments in thirty 85- to 125-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in the Oregon Coast Range foothills. Group-selection cuts had 33% of the entire stand volume extracted as patches approximately 0.2–0.8 ha in size; two-story regeneration harvests had 75% of the volume extracted, and 20–30 residual trees/ha were left; clearcuts had all trees removed, except for 1.2 trees/ha. One decade after harvest, tree basal area, diameter, and height growth, and crown width and fullness did not differ between silvicultural treatments. In contrast, live crown ratio was largest in clearcuts (0.74), and the proportion of trees with epicormic branching was highest in two-story stands (35%). Overall, 45% of trees had more basal area growth in the decade after harvest than in the previous decade. Residual green trees in clearcuts and group-selection stands experienced the highest and lowest percentage mortality, respectively (30.6% vs. 0.2%). Our results reflect little differentiation in the characteristics of trees growing under three silvicultural conditions one decade after harvest. However, percent residual green tree mortality increased with increasing harvest intensity.

Initiation of an old-growth Douglas-fir stand in the Pacific Northwest: a reconstruction from tree-ring records

We used tree-ring records to reconstruct the stand initiation of an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand in the western Cascade Range of southern Washington. All tree-ring samples were prepared and crossdated. Following a stand-replacing fire, the stand initiation period lasted from 1500 to 1540, with gradual filling-in of growing space over this period. All sampled Douglas-fir were initial colonizers, establishing (at stump-height) 1500–1521 under open conditions. A small number of the sampled western hemlock (Tsuga heterophylla (Raf.) Sarg.) were also initial colonizers. Growing space filled as tree crowns widened, and by 1540, closed forest conditions had developed. At this time, Douglas-fir were spaced about 3.5 m from equivalent competitors (ca. 800 trees/ha). In the centuries following canopy closure, considerable natural thinning of the initial colonizers occurred, but the canopy never opened enough again to allow further Douglas-fir establishment. Surviving Douglas-fir developed deep crowns despite the narrow initial spacing, and without epicormic branching from the bole. Most western hemlock that were canopy trees in 1992 established after 1540, originating in the understory. This reconstruction provides an example that may be useful where management policies emphasize the development of old-growth structures.

Epicormic Branches Affect Lumber Grade and Value in Willow Oak

A case study was conducted in a 50-yr-old bottomland oak stand in central Alabama to investigate the relationship between epicormic branches and lumber grade and value in willow oak (Quercus phellos L.). The stand had been thinned from below 7–10 yr earlier, resulting in a wide variety of epicormic branch conditions on the residual trees. A sample of 41 willow oak trees was selected before the stand was clearcut in late 1991. All merchantable logs in each tree were graded prior to felling. Average dbh of sampled trees was 19.1 in. Each tree averaged 9.5 epicormic branches on the sawlog portion of the bole. From these 41 trees, a random sample of 57 logs (31 butt logs and 26 upper logs) was shipped to a sawmill where they were sawn into lumber and graded. Epicormic branching had a large detrimental effect on log grade of individual trees. In general, as few as five epicormic branches somewhat evenly distributed on a 16 ft log was enough to cause a reduction in log grade. More importantly, defects caused by epicormic branches had a serious effect on lumber grade, particularly in the higher grades. Over 50% of the lumber volume that would have been graded as either First and Seconds or Select in the absence of epicormic branches was downgraded to No. 1 Common or below due to defects caused by epicormic branches. Based on lumber prices prevailing at the time of the study, defects caused by epicormic branches resulted in a 13% reduction in the value of the lumber produced in the final harvest. South. J. Appl. For.25(3):136–141.

Epicormic Branching on Pruned Coastal Douglas-Fir

In theory, pruning is an attractive silvicultural technique because there is a great potential for increased production of clear wood after its execution. Much of the currently available literature on the pruning of Douglas-fir (Pseudotsuga menziesii) concerns the effects of pruning on diameter and height growth. Other aspects of the pruning response need to be considered, because clear wood production cannot be guaranteed merely because the trees were pruned. The Stand Management Cooperative, headquartered at the University of Washington, conducted a regional study to examine how Douglas-fir trees respond to pruning. Epicormic branching responses are reported here. Some anecdotal observations, as well as some intuitive ones, are confirmed. Epicormic branching was most severe on the south and west sides of trees. When epicormic branching was severe, sprouts occurred both at nodes (or whorls) and along internodes. Less severe or moderate sprouting tended to originate mainly in nodes. The risk of epicormic branching is minimal as long as the pruning treatment does not reduce the live crown by more than 40% and the stand has 500 or more stems/ha. The highest risk of epicormic branching was found to be when the live crown is reduced by more than 40%, and the stand carries less than 500 stems/ha. West. J. Applied For. 16(2):80–86.

Effects of residual stand density on growth and volume production in even-aged red maple stands

The effects of five residual stand densities (9.2, 13.8, 16.1, 18.4 m2/ha, and an unthinned control (27.2 m2/ha)) on10-year stand and crop tree growth and bole quality were studied in an even-aged red maple stand in Michigan. A secondary treatment of removing the understory trees (5-10 cm DBH) was applied on half the plots. Diameter growth was significantly greater in all cutting treatments than in the control. Ten-year diameter growth in the heaviest cut treatment was nearly three times that of the control. The interaction between understory removal treatments and density treatments was significant for net basal area growth. Ingrowth in the heavier cut treatments accounted for a significant portion of net basal area growth in the plots without understory removal. Mortality was highest in the control and lowest in the heavier cut treatments. Epicormic branching significantly reduced clear bole length of crop trees in the heavier cut treatments, especially when the understory was removed. For these reasons, a more conservative first entry thinning level of about 17-18 m²/ha without controlling the understory is recommended for even-aged red maple stands.

Assessment of Residual Stand Quality and Regeneration Following Shelterwood Cutting in Central Appalachian Hardwoods

Partial cutting to develop two-age stands is a relatively new practice in the central Appalachian region, and forest managers need quantitative information in order to evaluate how well it meets management objectives. Typically, this practice leaves a residual overstory of 10 to 40 ft² per ac of basal area and leads to regeneration of desirable shade-intolerant species which comprise the second age class. In this study we evaluated residual tree quality and regeneration 2 to 5 yr after cutting in 20 stands on the Monongahela National Forest in West Virginia. Tree grades were not significantly affected by the cutting. The largest grade reductions, due primarily to epicormic branching and logging wounds, occurred with large white oak sawtimber (11%) and white ash small sawtimber (10%). Epicormic branching following the cut was greatest for white oaks in the suppressed and intermediate crown classes. Across all species, the trees in the lower crown classes produced the greatest number of epicormic branches. Overall, epicormic branching on the 16 ft butt logs of dominant and codominant trees was low. For white oak (Quercus alba), 64% of these trees produced no epicormic branches. But 75% of yellow-poplars (Liriodendron tulipifera), 82% of black cherries (Prunus serotina), 78% of northern red oaks (Quercus rubra), and 89% of white ashes (Fraxinus americana) produced no epicormic branches on butt logs. Logging wounds occurred on 45% of the residual trees across the 20 stands, but 21% had large wounds over 100 in². Regeneration of both shade-intolerant and tolerant species was prolific following the cutting. Total numbers of tree seedlings and sprouts ranged from 8,217 stems/ac in the mixed oak stands of the Ridge and Valley Province to 30,845 stems/ac in the beech-cherry-maple stands in the Allegheny Mountains. The birches, primarily sweet birch (Betula lenta), comprised the most abundant species across the study area, but species composition varied depending on forest cover type. Regeneration numbers were lowest in the mixed oak stands in the Ridge and Valley Province. North. J. Appl. For. 15(4):203-210.