Shortleaf Pine Sprout Production Capability in Response to Disturbances

Shortleaf pine (Pinus echinata Mill.) seedlings are capable of sprouting and continuing growth after the stem is killed. The sprouting ability of shortleaf pine could be used to favor the species silviculturally after disturbance. Information is limited on shortleaf pine seedling sprouting after burning and clipping at different periods of the growing season and the effects of these treatments during their first three years after outplanting. Survival, seedling growth, and sprout production of shortleaf pine were evaluated after burning and clipping. The research was conducted on one, two, and three-year-old seedlings on an above average productivity site on the Cumberland Plateau region of east Tennessee. Replicated treatments were analyzed as a randomized block design which included: clipping in March, burning in April (early growing season burn), burning in July (mid growing season burn), burning in November (late growing season burn), and an untreated control completed on one, two, and three-yearold seedlings. Each experimental unit received a treatment once over the course of the study. Variability in burn treatments and their effects on the dependent variables were accounted for by using burn duration and intensity covariates in the analyses for sprout number and height. Results indicate that survival improved with increasing age and was greatest in early and late growing season burns among burn treatments and improved even more with clip treatments. Sprout production following treatments was greatest with the late growing season burn across years and was affected by the maximum burn temperature and mean burn temperature covariates at different seedling ages. Height growth following treatments was greatest with the late growing season burn or clip treatment across years. The burn duration covariate affected seedling height in two-year-old seedlings. Taller seedlings post treatment tended to produce fewer sprouts. These results indicate that late growing season burns may be best to promote the greatest survival rates and sprout growth in the species.