forest management « TreeTopics

Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties.

Pretty much every landowner I know has a weed issue.

Some are fairly short term and narrow, such as controlling common weeds in a new tree planting. Others are much longer term and less defined, such as keeping invasive species at bay in the woodland, or perhaps encouraging native plants in a meadow or streamside restoration.

There are multiple approaches to weed management, including preventing new weed introductions, mechanical or physical control such as mulching or mowing and the use of herbicides. Most people use a mix of two or more of these approaches, with many including herbicides as one of the methods they use.

Here are some key resources to help you manage your weed issues.

Invasive Weed Identification and Management EC 1563

It is important to know the enemy, and this is a good place to start, beginning with the 3-page introduction. This publication goes on to describe the identifying characteristics, origin, habitat, ecology and management strategies for selected invasive weeds in the Pacific Northwest. This list is not inclusive of all invasive weeds, but focuses on the most dominant or potentially invasive species that plague us. Check PNW Weed Management Handbook for current herbicide recommendations.

The Nature Conservancy’s Weed Control Methods Handbook

A useful resource for many types of landowners, the Weed Control Methods Handbook: Tools & Techniques for Use in Natural Areas provides detailed information about weed control techniques including manual and mechanical methods, grazing, prescribed fire, biological control, and herbicides. Check PNW Weed Management Handbook for current herbicide recommendations.

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Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties.

In a previous article , I wrote that many folks in NW Oregon are growing too many trees in young stands given some common family forest landowners’ objectives, including doing a selective thinning harvest when the trees are in their mid-20s. While on their way towards a variety of longer-term objectives and stand conditions, most people are hoping that their initial harvest will at least break even (when it is sometimes called a commercial thinning). So we need to focus on reaching that first thinning harvest in a timely manner and leaving the stand in a good condition to meet future objectives. Let’s begin by looking at what it takes to have a successful thinning harvest.

My contacts in the business around the mid-Valley tell me that while the first thinning harvest should provide a mix of saw logs and chip logs, most of the surplus trees removed in the thinning need to produce a sawlog or two if you hope to break even or make a little money (a mix of around 2/3 saw logs and the remaining 1/3 chip logs is a rule of thumb used by some). Too many small logs and the operation is costing money. That sawlog will vary according to the mill it is headed to, but is generally 20 feet to 32 feet long with a 6 or 7 inch top. Smaller wood goes to chip and saw or pulp.

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Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties.

In my travels around the mid-Willamette Valley, I am seeing a lot of young conifer stands (generally Douglas-fir up to 20-something years old) with just too many trees. Why do I say there are too many trees?

I know many people in this part of western Oregon who are patiently waiting for their trees to grow, hoping to thin the trees in a selective harvest when the stand is about 25 years old. They plan to sell the harvested trees to cover costs and would like to break-even or make a bit back on establishment expenses.

All too often it is not working out that way. Instead, as the stand approaches the target age they find that trees have already become too crowded, with too many small, slow growing trees in the stand. The trees are still too small to support a profitable harvest thinning operation (also called a commercial thinning). To thin at that point is to do so at a cost, although it may be best for the woodland in the long-run. To delay the thinning and wait for the trees to grow enough to make the thinning harvest profitable is appealing, but deceptive. It may avoid the short term expense, but is likely to weaken the stand at a long-term cost of growth, stand stability and future options. It is a classic “pay now or pay later” situation.

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By Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties

Last month I spent a morning at OSU attending the annual science meeting of the Vegetation Management Research Cooperative (VMRC). It was well worth the time.

The VMRC’s mission includes conducting applied reforestation research of young plantations from seedling establishment through crown closure and, to promote reforestation success. The VMRC’s research has an emphasis on practical, operational vegetation control, and their research is broadly relevant and readily applied to the needs of family forest landowners, so I do try to keep up on their work.
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Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties.

For those so inclined, pruning season is now open.

There are many reasons people pick up a saw or loppers to prune up their trees in young stands. The most common motivations I hear are accessibility, aesthetics and fire resistance/prevention. Even pruning up just a single- eight foot “lift” can serve any or all of those objectives.

People want to be able to walk freely around the place without fighting through dense brush the whole way. So many prune to open trails or corridors. This allows them to get to favorite spots more easily, or just get around and see how things are doing. It lets them enjoy the property more (daily walks or bird watching) and also to more easily take care of tasks like spot spraying invasive weeds. Pruning a whole block of trees improves not just access but opens up the line of sight. It quickly changes the look and feel of a young stand and gives the stand an open aesthetic that many people like.

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Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties

I recently got a call from a fellow whose Douglas-fir trees were covered with globs of pinkish pitch. It looked kind of like candle wax drippings on a Chianti bottle in some Italian restaurant, except it was on the trunks of his trees. As we talked I discovered that it was not an old stand, and the landowner had been out during the nice weather last summer and pruned his trees up six or eight feet to make it easier to get around and to reduce the risk of fire down near the County road. The pitch blobs were at the pruning scars.

Pitch moth evidence on off-site ponderosa pine

The culprit here is the Sequoia pitch moth (Synanthedon sequoia), a common clear-winged moth that attacks many conifer species.

Although commonly seen in town in people’s shore pine and other ornamental pine species, it is not generally a problem on Douglas-fir, or native Valley ponderosa pine except when the tree is wounded. A common and very attractive wound is easily created by pruning live branches during the summer months (April thru September) when the bark is soft and the adult moth is active. Although unlikely to kill your trees it is unsightly and generally avoidable.

Prevention is the best cure.

So this summer, put down those pruning shears. Save that job for the winter months.

Have an image of pitch moth on Douglas-fir you would like to share? email brad.w-r@oregonstate.edu

Fresh pitch moth evidence on an ornamental pine

By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties

How do you like your silviculture served? In a book, a pamphlet, a video, or an app?

A sampling of silviculture manuals dating from the 1970's and 80's — A sampling of silviculture manuals dating from the 1970’s and 80’s

My office shelves are lined with decades-old research reports, mostly left behind by my predecessors; and having neither the time to sort through them nor the ability to fully shake my packrat tendencies, I hang on to them. Besides the information they contain, these volumes form a historical record of sorts, and so while they don’t come off the shelf too much these days, they are worth keeping around.

An example is Douglas-fir: Stand Management for the Future (1986). The title makes me consider whether the Future of Douglas-fir stand management has turned out the way the authors expected, when this was published nearly 30 years ago. Continue reading →

By Brad Withrow-Robinson, OSU Forestry and Natural Resources Extension – Benton, Linn and Polk Counties

Winter storms seem to inflict damage to trees and forests somewhere in the area most years. Winds, snow and ice can damage individual trees or entire forest stands- breaking out branches, snapping the main trunk or tipping over whole trees, leaving landowners with a mess and many unexpected decisions.

This winter has been an exception in the severity of the November 2014 ice storm that battered a swath of the interior Coast Range from the Kings Valley area south to Mary’s Peak (see previous article). This unusual event caused irregular and spotty damage reflecting fairly small differences in aspect and elevation. Many landowners are still surveying the damage and considering their need to salvage and wondering if they can thin the damage out while leaving a healthy stand. Damage is severe enough in some cases to be forcing the decision to clear cut and replant young stands rather than the early thinning they were due for.

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By Brad Withrow-Robinson, OSU Forestry and Natural Resources Extension – Benton, Linn and Polk Counties

A local meeting of professional foresters last month focused on how forest management practices reflect the objectives of the owners. That sometimes creates challenges for the managers, since owner and manager are often not synonymous when it comes to forests and other natural resource lands. Some objectives and corresponding management practices are very well defined and developed, and others much less so.

For example, lands managed for stockholders and other investors are often planted as even aged stands on fairly short rotations, since it is an efficient way to manage risk and provide a return on investment while also providing some additional benefits to society. There is good understanding and a pretty straight line between those objectives and managers activities, both of which have remained reasonably steady over time. Their management practices have been developed through applied research, so these managers are generally quite successful in meeting their objectives.

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By Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension, Benton, Linn & Polk Counties

The short answer, unfortunately is ”yes”, but the news was clearly mixed when researches and land managers gathered for the Annual Meeting of the Swiss Needle Cast Coop (SNCC) in Corvallis on December 4. They met to review progress in learning more about this native disease, how it affects trees and forests, and how to manage forests in the affected areas.

The meeting included updates on this year’s aerial survey, progress in establishing the next generation of research plots across western Oregon, the effects of thinning and other management activities on foliage retention and growth, and improvements in remote sensing and growth modeling abilities. Some of the things I picked up this year included:

The disease is intensifying but not expanding greatly. That is to say, we are certainly seeing more severe disease symptoms in places, but mostly within areas where it has been a problem before, and the footprint of highly affected area does not seem to be growing very dramatically. The disease was detected on over 586,000 acres in 2014, which is up significantly from 18 years earlier (131,000 acres in 1996). The main area of impact remains near the coast, generally within 25 miles, except for an active area around Mary’s Peak.

Thinning pre-commercially does seem to help improve needle retention, but only in the healthiest trees and in the lower part of the live crown.

Unlike other stressors, such as drought, it seems that SNC-weakened trees are not highly attractive to Douglas-fir beetles.

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TreeTopics

Serving small woodland owners and managers in the Willamette Valley and northwest Oregon

Tag Archives: forest management

Resources in the fight against weeds

Spacing young conifer stands

Many young stands too crowded

Understanding vegetation in young plantations: It’s what they do

Pruning season is now open

Put down those pruning shears

Silviculture information – from low tech to the world of apps

Winter Storm Damage

Management by Objective

Is Swiss Needle Cast still a Problem?

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