FRDA Report: Black Cottonwood and Balsam Poplar Managers ...
FRDA Report: Black Cottonwood and Balsam Poplar Managers ...
FRDA Report: Black Cottonwood and Balsam Poplar Managers ...
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Information Sources:<br />
Klinka <strong>and</strong> Feller 1984;<br />
Farmer 1990; McLennan<br />
1990; Winship 1990;<br />
McLennan <strong>and</strong> Mamias<br />
1992; McAuliffe 1993;<br />
Silviculture Interpretations<br />
Working Group<br />
1993; Klinka et al. 1994.<br />
Fortunately, because the value of cottonwood is increasing, managers may be able to<br />
justify such costs more readily. On the positive side, planting whips permits final spacing<br />
to be carefully controlled, which means that plantations can be established to meet<br />
spacing objectives for specific end products such as pulp logs or veneer. Under the<br />
medium-rotation extensive culture system practiced by Scott Paper Limited, experience<br />
has shown that no site preparation or st<strong>and</strong> tending is needed.<br />
In the case of balsam poplar, new reproduction can occur in several ways: from<br />
new stems originating from intact or broken roots; from preformed or adventitious<br />
buds on stumps or at the base of trees; <strong>and</strong> from buried stems <strong>and</strong> branches. Segments<br />
of stems of all sizes buried during logging can contribute to regeneration. For balsam<br />
poplar, this capability offers little reason for planting except in particular circumstances,<br />
<strong>and</strong> even then its capabilities are an advantage because, unlike aspen, it will readily<br />
reproduce by unrooted stem cuttings. Clonal differences are a major source of variation<br />
in rooting percentage <strong>and</strong> the number of primary roots produced by dormant cuttings.<br />
Stem cuttings have been the main means of st<strong>and</strong> establishment for short-rotation<br />
intensive culture of balsam poplar elsewhere, especially in the Lake States. In situations<br />
where special circumstances may make it desirable to plant balsam poplar, there are<br />
good opportunities for genetic improvement of yield, partly because this species has<br />
characteristics that facilitate breeding, <strong>and</strong> because of the ease with which it can be<br />
propagated by stem cuttings.<br />
Stump sprouts breaking off at the stump, especially from taller stumps, have often<br />
been observed. This suggests the need for better guidelines on preferred stump heights<br />
for optimum sprout production.<br />
In many instances, natural regeneration of cottonwood <strong>and</strong> balsam poplar is from<br />
both seed <strong>and</strong> vegetative sources. An advantage of natural regeneration is the cost<br />
factor; a major drawback is unevenness of spacing, which results in less than full site<br />
utilization. Vegetative sprouts initially grow more rapidly than seedlings <strong>and</strong> will shade<br />
out slower-growing individuals. Planting that uses wildling whips or nursery stock with<br />
controlled spacing offers an alternative if local stock adapted to local growing conditions<br />
is used. Planting also gives the forest manager the potential for manipulating st<strong>and</strong>s to<br />
enhance wildlife forage or habitat. After whip planting, st<strong>and</strong> tending is usually not<br />
necessary except for fill planting. However, the choice of whip planting requires a<br />
commitment to special care. Whips need to be carefully h<strong>and</strong>led <strong>and</strong> properly stored<br />
so that they are not desiccated at time of planting. As well, their buds must not be<br />
flushed at planting time. Even with these precautions, some mortality of whips should<br />
be expected.<br />
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