Regeneration and Restoration — Abstract of Paper


Stump Sprouting of Blue Oaks 10 Years After Harvest
Douglas McCreary,¹ Bill Tietje,² and Bill Frost³


A study was conducted at five sites throughout California to determine how the sprouting of harvested blue oak (Quercus douglasii) is affected by the date the trees are cut down, the height of the residual stumps, and whether stumps are protected by fencing or not. After 10 years, 34 percent of the stumps had viable sprouts. The greatest effects were from fencing. Four times as many protected stumps survived than those exposed to browsing animals. Most of the mortality in unfenced areas occurred since the last evaluation eight years ago. Twice as many 90-cm-tall stumps had surviving sprouts than basal-cut stumps, and these sprouts were both taller and had larger diameters. Differences among harvest dates were relatively small, but there were significant differences among sites for most variables evaluated. However, there were no clear site attributes to explain these differences. These results indicate that the cutting of trees in densely stocked blue oak stands can be used to alter the age structure of stands and foster the establishment of young sprout-origin trees. The replacement of even-aged stands with stands of varying ages may help mitigate the negative impacts of inadequate regeneration.