Stump Sprout Characteristics of Three Commercial Tree Species in Suriname

We compared stump sprouting by three common timber species in Suriname on the basis of sprout origins on stumps, sprout densities, and sprout height:diameter ratios. We then compared some leaf and stem functional traits of 15–18-month-old resprouts and nearby conspecific saplings of the same height (0.5–3.5 m) but unknown age. Stumps of Dicorynia guianensis Amsh. (29–103 cm in diameter) produced the most sprouts (x = 9.2/stump), followed by the 50–71 cm diameter stumps of Eperua falcata Amsh. (10.6/stump), and the 30–78 cm diameter Qualea rosea Amsh. (5.9/stump); sprout density did not vary with stump diameter. Sprouts emerged from the lower, middle, and upper thirds of the stumps of all three species, but not from the vicinity of the exposed vascular cambium in Qualea. With increased resprout density, heights of the tallest sprout per stump tended to increase but height:diameter ratios increased only in Dicorynia. Compared to conspecific saplings, sprouts displayed higher height-diameter ratios, higher leaf-to-wood mass ratios (LWR), and lower wood densities, but did not differ in leaf mass per unit area (LMA) or leaf water contents. These acquisitive functional traits may reflect increased resprout access to water and nutrients via the extensive root system of the stump. That we did not encounter live stump sprouts from the previous round of selective logging, approximately 25 years before our study, suggests that stump sprouts in our study area grow rapidly but do not live long.

The efficacy of Chondrostereum purpureum in sprout control of birch during mechanized pre-commercial thinning

The efficacy of mechanized pre-commercial thinning (PCT) done by a lightweight mini-harvester Tehojätkä together with the Chondrostereum purpureum (Pers. ex Fr.) Pouzar fungal treatment (dilutions 1:100, 1:200, 1:400) and control (cutting only) was studied for three years. The efficacy of the fungal treatment was defined as capability to prevent sprouting of birch (Betula pendula Roth. and B. pubescens Ehrh.). The fungal treatment resulted in higher stump mortality and lower number of sprouts but it did not have a clear effect on the maximum height of stump sprouts. However, mortalities obtained in this study (34.1%, 26.8%, and 25.6% for dilutions 1:100, 1:200, and 1:400, respectively) were notably lower compared to previous studies which indicate that the accuracy of the spreading mechanism was not satisfactory. We conclude that it is possible to decrease stump sprouting with the fully mechanized fungal treatment but putting this implementation into practice needs more testing to increase efficacy.