Thursday, May 22, 2008

Effects of Establishment Methods and Initial Seedling Size on Early Northern Red Oak Performance

In early 2006 the Virginia Department of Forestry installed a test of the effects of different establishment methods and initial seedling size on northern red oak survival and growth. There were two old-field locations, one in Louisa County and the other in Washington County.

Northern red oak seedlings from the DOF’s Augusta Forestry Center were graded into three root collar diameter classes – small (0.2 inches), medium (0.3 inches), and large (0.4 inches) and planted in early March 2006 using one of five establishment treatments: 1) no treatment; 2) VisPore mulch mat plus 4-foot Tubex tree shelter; 3) spot spraying of a 2-ft radius spot using a 2% glyphosate solution; 4) 4-foot Tubex tree shelter plus 2-ft radius glyphosate spot spraying; and 5) VisPore mulch mat only.

After two years, all the trees are off to a very slow start. Even the best of the seedlings have grown only about 1.5 feet in height and 0.06 inches in groundline diameter (GLD). But it looks like the way they are established (i.e. in tubes or not) has a lot more to do with their performance than does their initial size. And it seems as if the seedlings in the tubes are spindly - although surviving better and growing in height, they aren’t growing as much in GLD.

Comparing establishment treatments shows that the Tubex shelter was essential for survival / browse protection.

The VisPore mat and spot herbicide treatment resulted in similar survival and growth. There was no effect of initial seedling size on survival. The smallest seedlings have grown less than medium or large seedlings.

Without protective shelters, most of the seedlings in the study are either dead or in the severely browsed condition seen at left.

1 comment:

TNC_Forestry said...

West Branch Involved in Testing of New Tree Shelter for Forest Restoration

This May, TNC forester Mike Eckley and Penn State Cooperative Extension forester Dave Jackson began a three-year cooperative research project on the West Branch Research and Demonstration Forest. The study will help determine what differences, if any, occur in the growth and survival of northern red oak seedlings when using traditional four-foot tree tubes versus the new Tree Sentry Tree Incubation and Protection (TIP) System shelters. Summit Environmental Group of Ohio is the manufacturer and distributor of the new and innovative TIP System tree shelter; however its design was influenced by local Centre County Tree Farmer, Jim Walizer, who is known for his passion in tinkering on his family woodlot and his commitment to serving on the PA Chapter board of The American Chestnut Foundation.

The Tree Sentry TIP System is essentially a 4.5 foot black mesh with an inserted 18” plastic cone that, similar to traditional tree tubes, surrounds the young seedling offering protection from wind, competing vegetation encroachment, and wildlife damage. Furthermore, the plastic cones mimic the effects of a micro-greenhouse, magnifying and retaining more radiant heat, often resulting in accelerated root development and growth.

Approximately 180 northern red oak seedlings were planted within the Cabin-East Restoration Treatment Unit which had received a prescribed fire in 2007 and mowing of competing vegetation in 2006. The unit is located southeast of the Whetham Cabin on relatively flat sub-mesic plateau ground. Roughly half (90) of the trees were assigned traditional tree tubes and rot-resistant black locust stakes and the other half were planted with the new TIP System shelter and bamboo stakes. Jackson is particularly interested in evaluating the use of bamboo stakes, which if proven a viable option, could be a significant cost-saver in tree planting and forest restoration projects involving tree tubes/shelters.

As the first growing season for this project progresses, preliminary field data show that approximately 86% of the seedlings are alive and doing well. When comparing establishment/survival rates between the two shelter types, interestingly, there was a 93% survival rate associated with the traditional tree tubes and an 80% survival rate for the TIP System shelter. Furthermore, it was noticed that black bear damage has occurred, mainly in the form of knocking over tubes along with an occasional biting of the plastic or mesh. A total of 12 tree tubes/shelters were either bent over or pulled out of the ground. Surprisingly, 10 of the 12 bear damaged tree tubes were of the TIP System shelters. Overall, the extent of the damage was minimal and easily fixed with a few minor repairs. It was documented that the bamboo stakes did not brake, however they splintered, twisted, and cracked, therefore the damaged sections were cut off and the good portion of the bamboo stems were reused for staking.

Additional field notes taken on factors that may influence the results of this research include increased vegetation encroachment of hayscented fern and blueberry which is being monitored and will be treated with a glyphosate type herbicide when appropriate. Furthermore, gypsy moth impacts are severe as the overwintering population has expanded dramatically, likely to result in severe canopy defoliation of West Branch and surrounding forestland.