Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension agent, Benton, Linn and Polk Counties
Earlier in this series (click here), we talked about some of the reasons people are interested in growing a diverse forest, some of the key components of diversity, and also some of the many ways to enhance your woods’ diversity. The idea was to show that a landowner often has a very wide range of future options, but often needs to make choices and take actions to achieve their goals. I know this may have seemed academic to some readers, so we will share some examples of how this looks in practice.
A good example of managing for diversity to meet some specific wildlife and timber objectives is Cedar Spring tree farm near Airlie, owned by Dave Hibbs, Sarah Karr and their family.
Sarah is an avid birder, determined that any property they own provide benefits for wildlife as well as for her family. Dave is a retired OSU forestry professor interested in producing future high quality timber along with other benefits from their woods. So, Dave and Sarah are typical of many families, with co-owners having some different objectives and priorities. But they have a willingness and ability to manage for multiple objectives that can be met by growing a diverse forest. So let’s take a look at some of the ways they do this.
It began by thinking about and writing down what they are trying to accomplish. They have a management plan that lists their goals. Developing this plan together forced them to be clear about their individual priorities and then to decide how to combine them in a way that works for both of them.
They then considered places on their property that are most critical to, or perhaps best suited to meeting each of those objectives. Different parts of a property naturally lend themselves to some objectives better than others. An important step towards limiting conflicts between sometimes-competing objectives is not expecting to accomplish everything on every acre.
Together these two steps help them refine and focus their efforts. For example, among the species Sarah is particularly keen on is the band tailed pigeon, a migratory bird that is abundant on their property each summer. The main attraction for the band tailed pigeon is the natural mineral spring in a small meadow. With this as the habitat cornerstone, Sarah is interested in providing other important habitat needs. Besides maintaining the open meadows around the springs, this includes providing tall roosting/perching sites and also many berry producing trees and shrubs. That is, they have identified specific parts of species diversity (berry producing trees and shrubs) and structural diversity (open meadow near the springs and tall perch trees) that are important to manage for.
This takes us to some of the specific management practices discussed in earlier posts.
They spent their first decade of ownership controlling invasive weeds, mostly blackberry and scotch broom that were taking over. These weeds were closing in the meadow, making the springs less accessible for the pigeons and, elsewhere on the property, out-competing many other plants, including the young conifer trees. They replanted large areas where trees had been lost to weed competition, mixing in clumps of some different species such as cedar and pine where suited. Aggressive weed control served both of their key objectives. But the execution was different for Dave and Sarah than it might be for other landowners focused only on timber production, where any non-conifer tree or shrub may be considered a weed. Native fruiting trees and shrubs such as madrone, blue elderberry and dogwood were favored, tolerated or treated as a weed, depending on their size, location, and competitiveness. That is, they controlled competition while keeping a lot of natural diversity.
They have spent the following decades tending the woods with a similar approach, depending primarily on thinning and perpetual weed control by mowing or spraying, as appropriate to enhance or maintain diversity.
Not long after finishing replanting some areas, Dave began thinning the young stands. The objective there was to adjust densities to meet key timber growing objectives and also, to maintain the species diversity of the stand. Without thinning, and particularly without including “maintaining diversity” as one of the thinning objectives, much of the diversity in some stands would likely have been lost, with little but the fastest growing species surviving the first intense crush of competition.
Dave decided in some cases and locations to remove competing hardwoods, and in others to promote them by removing a competing conifer. This choice clearly benefited the wildlife objective at the expense of future timber production. But it was a calculated tradeoff, applied in some places, and not in others. Some of those trees killed or left to die are turned into snags, providing another important part of structural diversity.
Dave and Sarah now have a property with a diverse mix of stands and a robust population of band tailed pigeons visiting each summer. Many other birds and animals live there seasonally or year-round too.
So there you have a short example of how someone is growing a diverse forest to meet multiple objectives. It has taken some thought, purpose, and understanding of how trees grow and compete, along with a significant amount of work. It sometimes has an opportunity cost in less efficient timber production. But then, efficient timber production often has an opportunity cost of less diversity or less effective habitat production. That is something each landowner can and should decide for themselves. In this case, these two objectives are met largely by managing different parcels for different primary objectives. The meadow and springs are for the pigeons, as are some very diverse stands nearby. Other stands are clearly dedicated to long term timber production.