from Nov. 1999
Planting Trees Takes Planning
John Belton

Joe had called in a rather excited state on a windy morning in late February, just three days after the county assessor had told him “his property taxes would go up if he did not plant some forest trees on the five acres behind his house”. Historically, Clackamas county was rather lax in holding property owners to the minimum forest stocking levels (over 200 trees/acre and free to grow) when there was a small acreage involved. Now this is not true and many small properties zoned forestry must be planted to trees or get taxed at a higher rate. Joe wanted me to advise him on the species and methods of planting trees. As I drove around the tool shed and saw the property to be reforested it was obvious this MWM assignment was not going to be solved with a quick visit and a hand shake over a cup of coffee.

About eight sapling fir trees were evident in the front of the field but the most abundant vegetation was some tough grass sod interspersed with two clumps of blackberries that had grown much higher than my head. It was evident that the front portion of the property had, at one time, been a mini motor-cross racetrack for dirt bikes. The grass could not hide the fact that soil compaction had taken place in the ruts of the abandoned racetrack and ample water was standing in the depressions created behind the mini jumps. Joe soon joined me and provided a short history on how the property had come to this condition. He also said that his wife was wanting to plant noble fir rather than other forest species but he wondered if noble would be able to grow fast enough to get up over the grass. Additional challenges to good forestry became evident as we continued toward the back of the property and walked down the steep hill. Although horses had been removed from the property five years back the soil retained some grooved trails but the water drainage was much better. The acre of ground at the bottom of the hill had one tall cottonwood tree and willow thicket, both indicating poor drainage in the clay soil.

It was clear that the tax assessor had gotten Joe’s attention but the good news was that he did not need to complete the entire reforestation in one year. The assessor would come back in three years and there should be “significant progress”; all reforestation should be complete in five years. We developed a plan so the most important priorities could be completed in the first year.

1. It was obvious that the grass sod was going to prevent good survival of any forest species he could plant that spring. As I was discussing the risk from mice girdling any newly planted seedlings Joe’s dog franticly started to dig and soon produced one field-mouse but that would be only one less from thousands. Joe’s wife was not enthusiastic about the use of herbicides but when I explained only three ounces of Oust per acre would kill the grass and that no amount of disking would be able to prevent resprouting, she was willing to make an exception. Joe was pleased to learn that the spray could be put on with a hand sprayer and in any kind of weather; it is taken up through the root system. Joe was to spray the flat ground in March and cut down the blackberries so he could lightly work the soil during the dry summer months and plant the first trees one year later. It was obvious the clay soil on this flat ground had poor drainage and would be totally unsuitable for noble fir. The soil compaction on the front of the property would quickly dry out each summer and prevent the best growth of Douglas-fir. Both ponderosa pine and red cedar have the ability to grow in poorly drained clay soil but the pine might be a bit better tree selection if there was a lot of wind or if there was not much organic material in the soil. Cedar trees can develop a shallow root system and tip over in strong wind if they grow on clay soils.

2. The second year would be devoted to preparing the steep slope for planting. Both Joe and his wife agreed to control a few large clumps of big-leaf maple and hazel brush growing in this area by repetitively cutting the sprouts, a labor intensive practice to avoid further use of herbicides. This was the area to plant Douglas-fir if they were interested because the soil compaction was limited to a few horizontal horse trails on the slope.

3. The acre-plus area at the bottom of the hill presented some of the greatest challenges but also offered a potential for greater creativity in their young forest. There was patch of skunk cabbage in the corner of the property that was just starting it’s spring growth phase. Joe recognized the importance of keeping all equipment out of this “wetland” but some of the small brush species in the other corner of the property could be controlled if the neighbor came through the fence with his small crawler tractor. This activity would expose mineral soil and could result in an aggressive reseeding by the large cottonwood tree. Another option might be to kill the large cottonwood by girdling and planting red cedar trees. The large dead cottonwood would provide habitat for many cavity dwelling species as it begins to decay.

This client report illustrates the importance of controlling competing vegetation prior to planting any forest seedlings. It also emphasizes the importance of matching species with soil type and other local conditions such as wind or wildlife control. Whenever a tree farmer starts a reforestation project like this it is important to take pictures of the area before, during and after the project has been completed and file them away for later reference. Editor’s Note: John Belton explains some advice and recommendations that he made when making a Master Woodland Manager (MWM) family tree farm inspection.

If you would like a free MWM inspection of your property either contact the OSU Extension Service in Clackamas County at (503) 655-8631 or contact your local County Extension Agent.