Harvesting cash (and biodiversity) from marginal land


By Amanda Kimble-Evans

What to do with marginal land on a farm is a question organic and sustainable growers are almost forced to address when creating their farm plans. Letting marginal land revert to native and wild areas can increase biodiversity by leaps and bounds, but this also means zero income from those areas—a hard decision to make for transitioning farmers especially. And agroforestry, a fairly well-known if not much practiced form of intensive land use, is rarely used in marginal areas in the U.S. The more common agroforestry techniques involve incorporating crops or livestock into existing woodland areas or incorporating trees into crop land.

The Tree as a Crop (TAAC) project at Rodale Institute was launched in 2009 as an agroforestry answer to the question of marginal land. By planting saplings in under-utilized areas of the farm where traditional crops won’t grow, farmers have an opportunity to create additional income and add value to their land. By sustainably managing trees—as one would with any other crop—a farmer can yield both environmental and economic benefits.

Don Jantzi, field operations foreman and orchardist, was out planting the latest round of trees earlier this spring and shared the process we’ve been using to select locations and varieties, to plant effectively, and to keep the copses growing well with a low-maintenance program of up-keep.

Location, variety, location

“We choose this area because it contained quite a bit of marginal land. The sloped upper area is incredibly dry and the lower area is really wet,” says Jantzi. “Although the middle area is arable land, we wanted a big area in trees and this seemed to work best for showing the various options for landowners.”

In 2012, we planted slow growing swamp oak, scarlet oak and red oak as well as fast growing black gum, sycamore, red maple and tulip poplar in various marginal locations around the farm.

Jantzi is planting this particular area with four varieties that suit the mixed landscape well. Swamp white oaks are going in the bottom area where it is wet, chestnuts and red oaks are being planted in the upper area where it is quite dry and scarlet oaks are going in more balanced middle area.

“We didn’t plant all the way up the sloped area simply because the young trees still need a substantial amount of water and we didn’t want to be watering all the time,” says Jantzi. One thing that makes Tree as a Crop attractive to farmers is that it is an ‘easy’ crop that can, over time, provide an extra income stream. “If it becomes a time suck, you lose one of the key desirable features,” says Jantzi.

When making variety selections, it’s important to find a balance between what will grow well in a particular area and what you think you can market 10-50 years down the road. Hard woods like oak are slow growing and can be sold as veneer- or cabinet-quality timber, but we’ve also planted red maple, tulip poplar and sycamore. These are lower quality but faster growing varieties and can be harvested in between oak growth to be marketed as pulp wood or firewood.

Spring versus fall, bare root versus container

While most trees can be planted anytime during the dormant season (fall through early spring), we actually recommend spring planting. “Most growers have more time to dedicate to putting a few trees in in the spring and there is a good amount of moisture to give the saplings a strong start without a lot of effort,” says Jantzi. Fall-planted trees might have more an opportunity to develop a root system over the winter, but heaving can be a problem. In areas considered marginal due to higher moisture content, freezing and thawing can push the newly planted trees up out of the ground leaving them exposed, meaning more work pushing them back into the ground in the spring and a higher potential for losses. Planting in the fall is still an option in normal to dry areas, but farmers may still prefer the timing of spring planting and the saplings can be just as successful.

Most saplings come as either bare root or containerized. While containerized trees can cost five times as much as bare root trees ($20 compared to $4 per), they have a much higher survivability rate. Containerized trees also give you a two- to three-year head start over bare root trees in terms of growth and development. Depending on the cost of losses, the difference in savings when going with bare root trees might not be quite as wide. Ultimately, budget and scale will play primary roles when making your final decision on container versus bare root.

Getting them in the ground

Spacing will depend, in part, on the size and shape of the area you’re planting. The general rule of thumb can be anywhere from 10 to 20 feet depending on variety of tree. We planted alternating rows (hard and soft woods) with 15 feet in between, but you can also do a four-row scheme with the two outside rows being soft woods and the two inside rows being hard woods. Leave 15 feet between the outside soft woods and inside hard woods, 20 feet between the two rows of hard woods.

Now for the actual planting…

Dig hole: If your soil is fairly loose like ours, the hole doesn’t have to be really wide. If you’ve got clayey soil, you’ll want a wider hole to allow for better root growth and spread.

Site your tree: The top of the root ball should sit flush with the top of the surrounding soil.

Fill the hole: Refill the hole, but don’t pile additional soil around the trunk. “Pot soil should be visible once the hole is filled,” says Janzti. Tamp the soil down with your feet to avoid lower soil around the tree due to settling.

Add protection: Hammer in a stake, attach a protective tube and top with a netting sock.

Protect and maintain

For optimum quality at harvest time, you want your trees as straight and uniform as possible. If you nick the wood or it gets nibbled by a deer you take it from veneer-quality down to cabinet-quality wood. Providing a level of protection while they’re young, tender and especially attractive to browsing animals could be beneficial in the long-term sales potential from your stand of trees. Tree shelters or tree guards are plastic tubes that protect the young saplings for the first three to five years of growth. The native plant nursery from which we purchased our trees (Octoraro) also sells Tubex tree shelters. These tree shelters also come with bird netting sleeves that fit on top of the tubes. The netting has a two-fold benefit. It prevents young birds from falling into the tubes and getting stuck, and, as the tree  grows over the top of the tube, the netting should help prevent additional nibbling by deer. If browsing animals aren’t a problem in your area, you could forego the additional cost and effort involved in using tree shelters.

Mowing is also important as the trees are getting established to prevent competition and strangulation. We mow a few times throughout the summer and then an especially good trim is necessary in the fall. Keeping the area super clean around the tubes may take a little more time with a string trimmer, but can pay off in spades. It is important to keep the area immediately surrounding the trees fairly bare in the fall to prevent mice from nesting in the tubes. We experienced quite a bit of damage our first year with mice. “They had a warm and cozy place to nest and they stayed there all winter chewing up the bark, trunks and roots,” says Jantzi. “Keep an eye out for weeds and vines growing up inside the tubes, too, and be sure to clean them out before winter.”

We’re just beginning to experiment with ground covers in TAAC. In 2012 we planted low-growing, ground covers with the idea of preventing weeds without interfering with tree growth. The goals were for long-term ease in maintaining the area and reducing the amount of mowing required. Unfortunately low-growing, low-maintenance ground covers also grow slowly and were unable to out-compete our weeds. We have a lot of grass, thistle and other agricultural weeds and still had to mow to prevent them from taking over. In doing so, we may have hindered the establishment and growth of the ground covers. “It may be better to mow once a month and not worry about the ground cover, but we will see how they overwintered,” says Jantzi. This year we will be working on a better method for easily establishing an appropriate ground cover.

Visit the Tree As A Crop section of our site for more information on the project and a list of additional resources. {LEARN MORE}

One Response to “Harvesting cash (and biodiversity) from marginal land”

  1. Jo Moss

    i am currently planting my wet land with various willow species and plan to use them as a coppiced fodder for horses. i understand this was common practice for hundreds of years. Do you know of anyone currently doing this?

    Reply

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