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

A free-to-grow tree coexisting with its early seral neighbors
A free-to-grow tree coexisting with its early seral neighbors

Early seral…it’s one of the biggest buzzwords in Pacific Northwest forestry these days.  But what is it? Put simply, early seral refers to the first stage in forest development following any disturbance, including wind, ice, fire or logging. An early seral, or early successional community is made up of the first colonizers of a forest opening: grasses, other herbaceous plants and broadleaf shrubs. Continue reading

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

In previous installments of this series on the basics of herbicide use in weed control, I distinguished between foliar and soil active herbicides, describing foliar herbicides as those applied to the leaves or stems of plants to be absorbed and carried throughout the plant to affect control. In the previous post I began discussing foliar herbicides in more detail with an overview of glyphosate.

In this entry I will look at a group of herbicides called “growth regulators” that include some important foliar herbicides and popular weed and brush killers commonly used in forestry, agriculture and habitat restoration. Continue reading

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

In my previous installment of this series on the basics of herbicide use in weed control, I distinguished between foliar and soil active herbicides. In this post I begin discussing foliar herbicides in more detail. Note: The attention given to herbicides in this series does not indicate an advocacy for their use but an acknowledgement that using herbicides presents some unique risks, and that landowners and managers need to know enough about them to make informed decisions on their use.

Foliar herbicides are applied to the leaves or stems of plants to be absorbed and carried throughout the plant to affect control. They are common and widely used to control annual and perennial herbs and also woody shrubs. Continue reading

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

Weed control is a top of mind topic now for many landowners. Following this spring’s strong log market, a lot of folks will be reforesting a harvest unit. Others may be planting a field of Christmas trees, or a swath of trees and shrubs as a restoration project to improve habitat conditions. And it seems everyone is struggling to control one invasive weed or another on the property.

While a number of approaches and strategies (including mowing, pulling and mulching) can and are used in managing weeds, many people will use herbicides as at least part of their approach. This is no surprise given their demonstrated effectiveness and efficiency. But not all users are well-versed in vegetation management, or the science behind it, so some review of herbicides seems to be in order. The attention given to herbicides in this and later articles does not indicate an advocacy for their use but an acknowledgement that using herbicides presents some unique risks, and that landowners and managers need to know enough about them to make informed decisions on their use.

Now, it is important to realize that one need not be a crop scientist to use herbicides. The label gives instructions that ensure the safe and allowable use of an herbicide, so the label needs to be read and followed. But responsible and effective use of herbicides requires some additional understanding about herbicides and how they work, as well as knowledge about the life cycle and other characteristics of both crop and target plant species they will be used with. Let’s begin talking about some basics. Continue reading

Although a significant challenge, successful planting and establishment is of course only the first step towards restoring a forest. Moist tropical forests tend to have much higher tree species richness and diversity than do our temperate forests. While a forest in the Coast Range or Cascades of Oregon may have a dozen or so trees and shrubs (and is often dominated by just a few tree species) a similar area hill evergreen forest in Northern Thailand may have 100 to 150 species.
Replicating or recreating this diverse forest in one fell swoop at planting is impractical, or impossible. There are significant challenges of producing so many species in the nursery and also, many species seem poorly adapted to the harsh conditions of abandoned farm fields, and simply do not survive and prosper. Restoring a forest means restoring conditions and processes which in turn help create the forest.
After screening over 400 species, FORRU selected about 20 hardy species to plant as the “framework” for the future forest structure and processes. Species were selected according to their suitability to nursery production, survival and growth in abandoned field conditions, as well as to represent different growth forms and several successional stages. A great many of the selected framework species bear fruit, which is meant to encourage birds to visit the site in the hopes that they will carry in other native species. This is a key idea behind the framework species approach (adapted from Australia): along with changing the physical environment (light, leaf litter and organic matter) to favor establishment and survival of additional species, the planting needs to encourage mechanisms that deliver those species to the site. Initial findings are promising, with an increase in the number of birds and small mammals observed, and over 70 additional tree species recruited to the study plots.
But what will be the fate of those new seedlings? Does their presence today tell us what the future forest will be?
Most foresters and woodland owners in Oregon have seen a carpet of seedlings emerge on the forest floor following a thinning or other disturbance that lets more light reach the ground and maybe exposes some soil. Douglas-fir, grand fir, hemlock, alder and maple may all show up in abundance. Familiarity with our local species tell us that the fate of these seedlings is not the same. Douglas-fir generally will not grow to maturity in those conditions, while the hemlock or maple might.
Hathai (my graduate student) is trying to develop a similar understanding of the trees which make up the hill evergreen forests in Thailand. Her work on the regeneration dynamics of trees in the understory should help people here in Thailand have a better idea of the likely fate of the seedlings, and if their arrival heralds development of more complex and diverse forests in the future. Her work may also suggest ways to manage the plantings to best meet the restoration/management goals.


Brad Withrow-Robinson

If you have called or emailed me recently, you have received an “out of office” message saying I would be away in February. The full story is that I am in the mountains of Northern Thailand, helping my graduate student, Hathai, with her dissertation research on forest regeneration dynamics of understory trees. Her work is part of a bigger effort at Chiang Mai University (CMU) to study how to restore diverse, seasonally-dry tropical forests.
Thailand has lost over half its forest areas in the last 40 years to unsustainable timber harvest practices and land use conversion. In the mountains of Northern Thailand, most forest loss and degradation is driven by a history of shifting agriculture. Abandoned after farming, much of this land becomes dominated by aggressive invasive perennial weeds which prevent forest regeneration both by directly competing with seedlings and also by feeding widespread fires each dry season (March-May). These fires are not part of the natural fire regime, but are human-origin fires that kill many of the young seedlings getting established naturally, or as part of planting efforts. This favors and perpetuates the weed communities rather than native forests.
The Forest Restoration Research Unit (FORRU) at CMU has been working on this restoration challenge for the past two decades. The FORRU team began their work with basic research on local forest trees, studying life cycles, flowering and fruiting phenology. Likewise, they tackled challenges in nursery production by testing germination and nursery cultural requirements to help them grow and plant viable seedlings. All very much as was done in the Oregon four or five decades ago.
Success in the field came by both controlling the weeds in the plantations for several years after planting (no surprise to us in Oregon) and very importantly, through rigorous and on-going community-level fire suppression.


This work has paid off, and they have made great progress in learning how to begin to put forests back on the landscape.

Brad Withrow-Robinson

Planting trees is a central part of woodland ownership. For many folks, planting was the first thing they had to do upon buying cut-over land. For others, it is part of leaving things better than they found them, of leaving a legacy or creating opportunities for the next generation.

Planting is a critical step towards growing a new forest, whether you are reforesting a harvested unit, or converting pasture or other farm ground to a riparian buffer. But it is not the first step in the process. That began a year or more ago with a look at the ground to decide what to plant and how to prepare the site. It continued with the work done to be ready to plant, and will go on a few more years after the seedlings are in the ground. At each step, in each season, success comes from focusing on the task at hand.

I was reminded of this when I was out visiting Bob Feldman last month. Bob and his family tend about 350 acres of conifers, oak woodlands and Christmas trees in the Eola Hills northwest of Salem in Polk County.

We walked down the hill to a 6 acre clear cut he harvested last summer. Before the logger left with his equipment, Bob had him deck some logs for firewood and pile the excess slash for burning. The site looks great, ready to plant.

So now Bob is ready to go with his ground ready, 2-0 seedlings ordered and planting crew lined up. After picking them up from the nursery, he will store his seedlings in a local cooler, pulling out a day’s-worth at a time to keep them in the best condition possible.

Bob stressed the importance of lining up a good contractor, someone with experience and a record of success they can demonstrate. Be sure to oversee their work, establish accountability and to make sure they do a good job. How? Get out there with them. Spend a good part of the first day with them, and a little time each day after that. Make sure you have explained how you want the job done, and to show that you care that it is done right. Check to see that things are being planted at the agreed spacing. Dig up a few seedlings to see that they are planted correctly, snug, at the right depth and not J-rooted. Check across the planting crew, and bring concerns to the crew leader. When finished, go out and look to see if you got what you asked for.

Good advice. But what if you are the leader, and the crew is your family? Bob has lots of experience there too, and says if they are new to it, then you have to teach them how to do it right. Stay with them and supervise until they get the hang of it. If adults, they should be as interested is getting it done right as you. If kids, their interests are a bit more complicated. Be patient with kids. As important as it is, you are teaching them more than “green side up, brown side down.” You are teaching them how to grow a new forest.

Brad Withrow-Robinson

One of the guiding principles of the Extension Service is to be a source of research-based information. Research-based? Meaning that the information we provide is not supposed to be based on rumor or anecdotes, but is supported by science.

University researchers are obviously an important source of our research-based information. Nonetheless I believe that “research” and “science” come in many forms and on many scales. Many woodland owners like to experiment on their own forests to come up with management techniques that work for them.

I’ve found this especially to be the case when it comes to preventing deer and elk damage to western redcedar seedlings: from painting seedlings blue to scare tactics, I think I may have heard it all. Are these experiments “research”? Maybe – it depends on how they are set up and measured.

Western redcedar and Sitka spruce in the same planting hole. Photo by Glenn Ahrens

Recently a forest owner wrote to ask about one such browse deterrent method whereby a cedar and a spruce seedling are planted together (see photo). (The hypothesis: the animals are deterred by the sharp spruce needles; the spruce thereby protects the cedar; eventually, when the cedar has grown above browsing height, the spruce is carefully cut away.) The individual wanted some specific guidance on how to do this, and wanted to see a demonstration site. Although we know that people have tried this method, to our knowledge none of these plantings were carried out in a scientifically valid way. We can provide a hypothesis on how things might turn out, but to date we do not have research-based information to provide. Instead, we can only rely on anecdotal evidence.

I’m a strong advocate for woodland owners contributing to our collective knowledge of woodland management by trying out different techniques on their own properties. However, there are several important design factors to keep in mind if you want to call your experiments “research”:

  • Have a control. Suppose you planted 100 cedar/spruce in the same hole, but did not plant any cedar without spruce. If the cedar are not browsed, it is not possible to know whether the spruce had any effect. It might just be that the deer were not hungry that year. In a controlled experiment, you leave a portion of the area untreated, or without the variable whose effect you are trying to test.
  • Have a large enough sample size. Suppose you only plant five spruce/cedar combinations, and of them, two cedars are browsed and three are unbrowsed. It is hard to draw a conclusion from five seedlings. Was the treatment 60% effective, or did the two browsed trees happen to be unluckily planted right along a deer trail? If you had planted 50 spruce/cedar combos, and only two were browsed, then it is easier to say that the technique is effective.
  • Replicate. What works on a north slope in Columbia County may not be effective on a south slope in the Willamette Valley; what works in a dry year may not work in a wet year. By repeating the entire experiment in more than one year or on more than one site, you can draw conclusions that have more power. This is probably the hardest one for small woodland owners to pull off individually. However, collectively there are a lot of experimenters out there. What if we could compile the results from everyone’s scientifically valid experiments? Then we might have some real research-based information (and some real value to all you frustrated cedar growers).

Thursday, July 7th, 6:00 – 9:00 pm
Forest Grove
“Keeping Your Little Trees Growing”

This gathering will be an opportunity to talk about reforestation challenges and strategies to keep your planted seedlings growing strong. What’s worked (and not worked) for you? Come ready to share your experiences with weed control, animal damage, insects and diseases, and other concerns. We will look at some young trees of several species planted by host Robin Lindsley on her small property, and talk about her efforts to get them “free to grow”.

Whether you are new to managing your land or a seasoned pro, all are welcome and encouraged to come. WOWnet events are designed for participants to learn from one another. And who doesn’t like a potluck in the summer!

For details and directions, view the flyer.


This is the big weekend for tree sales. Here’s the rundown for three sales, all happening Saturday, March 12th.

Columbia County Small Woodlands Association tree sale: 9:00 am – 2:00 pm at Lawrence Oil in St. Helens. Bareroot seedlings including Douglas-fir, western redcedar, grand fir, ponderosa pine,coastal redwood, port orford cedar, noble fir,  Oregon ash, and a variety of ornamental species. First come, first serve – arrive early for best selection!

Washington County Small Woodlands Association native plant sale: 9:00 am – 3:00 pm, Bales Thriftway in Aloha. A wide variety of container size trees, shrubs, and forbs. See the full list and details by clicking this link.

Weyerhaueser Public Seedling Sale: 8:00 am – noon, Aurora Forest Nursery. About a dozen conifer species of various stock types on sale as well as some hardwoods. Major forest species sold by the bag or in small quantities. All the details are here.

Happy planting!