Bottomland Hardwood Reforestation In The Lower Mississippi Valley

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WHY REFORESTATION?

We prepared this bulletin to assist you--as a farmer or other private landowner--in reestablishing forests on part of your land. It will be most useful to you if your land is in the Lower Mississippi Valley and your main reason for reforestation is to produce wildlife habitat, either for private enjoyment or as a means of obtaining supplemental income. In addition to more wildlife, you can expect numerous other benefits if you reforest part of your land.

Several of the non-wildlife related benefits of reforestation are economic, such as the additional income that you may get from participating in conservation-related agricultural programs or through selling timber. Some benefits are environmental such as the improvement in water quality that may result if you reforest an area between a field and a waterway. Other benefits are less tangible, but may nevertheless be important to you. One example is the personal satisfaction of watching your forest grow and mature--and realizing that you are producing something of value to yourself, as well as to your community, the Nation, and future generations.

Value of Lower Mississippi Valley Forests to Wildlife
The bottomland hardwood forests of the Lower Mississippi Valley provide some of the best wildlife habitat in the entire United States. If you own a tract of forest anywhere in the valley (Figure 1), the chances are very good that it is home to a wide variety of both game and non-game wildlife species.

Studies have shown that, acre for acre, bottomland hardwood forests of the types found in the Lower Mississippi Valley can support two to five times as many game animals as nearby upland forests. Deer, turkeys, squirrels, rabbits, mallards, and wood ducks are all taken in great numbers from forests throughout the valley each hunting season. Otters, minks, raccoons, nutrias and other important furbearers are found throughout much of the Lower Mississippi Valley’s forests. When flooded, these forests also provide spawning sites and food for several species of game and forage fish. Throughout this bulletin, you will find drawings of some wildlife species that favor bottomland hardwood habitat.

Many types of non-game wildlife also make extensive use of Lower Mississippi Valley forests. Millions of migratory birds move down from the north to spend the winter in the valley, at which time these forests may have 10 times as many birds per acre as upland forests. Several species of non-game wildlife found in these forests are threatened or endangered. For example, it is likely that North America’s rarest songbird, the Bachman’s warbler, still survives somewhere in the forests of the Lower Mississippi Valley.

Losses of Lower Mississippi Valley Forests
Prior to the arrival of the first European settlers, the Lower Mississippi Valley was almost entirely covered by dense bottomland hardwood forests and cypress-tupelo swamps. In many places, these forests overshadowed vast, nearly impenetrable thickets of cane or palmetto. There were just a few exceptions to this heavy cover of forest. Two of the most notable--the Grand Prairie region of Arkansas and the Macon Ridge area of northeastern Louisiana--were largely devoid of trees because of soil conditions and perhaps in part because of frequent burning by Indians.

The tremendous agricultural potential of the valley, due to its rich alluvial soils and adequate moisture, was realized almost immediately, but the rate of clearing and conversion to agriculture was slow at first because of the frequent flooding and lack of drainage. Gradually, as the Mississippi River and its tributaries were brought under some control and coordinated drainage projects were established, more and more of the forests were cleared.

By the late 1930’s only about half of the original area of forest remained. Clearing continued at a rapid pace right up through the late 1970’s, by which time only about 20 percent of the original forested area remained (figure 3). While the rate of clearing has begun to slow down, it is also apparent that many of the areas that have already been cleared were better suited as forest than as agricultural land; many of these lands can successfully produce a crop only in relatively dry years.


PLANNING FOR REFORESTATION

Careful planning is the first, and perhaps the most critical, step in the reforestation process. You will have to choose a planting site and decide whether or not there is a need for site preparation; you will also have to choose which species you will plant and the planting method you will use. You should make these decisions well in advance of the planting date--ideally in the summer or early fall prior to planting--to ensure the availability of labor, equipment, and planting stock.

Choosing the Planting Site
Reforestation, should take place primarily on lands least suitable for agriculture. In general, such sites will be fields on the lower portion of your land which have poor drainage or are subject to frequent flooding. Other recommended planting sites include the edges of rivers, streams, borrow pits, drainage channels, farm ponds, roadsides, and fencerows. You might also want to consider reforesting areas that would join two existing tracts of forest since this can provide valuable travel corridors for wildlife.

Where possible, combining reforestation with other types of wildlife management can be beneficial. For example, if you would like to convert a large, low-lying fields to wildlife habitat, you could maintain the very lowest portion as a seasonally flooded shallow water impoundment for wintering waterfowl and plant the surrounding portion of the field with trees. In such a case, the forest may enhance the use of the impoundment by waterfowl, perhaps by sheltering the impoundment from disturbance caused by a nearby road or residential area. Also, the impoundment may increase the value of the forest to wildlife such as deer and turkeys by providing a source of water and additional food.

Once you select the planting site, you should obtain information on its soils and flooding characteristics, since these will affect your selection of the tree species. A good place to start is with the county or parish soil survey, which you can obtain through your county or parish Soil Conservation Service office. Soil surveys contain a wealth of information on the soil characteristics (including degree of flooding and soil saturation) that affect the survival and growth of trees, as well as information on the suitability of the soil type(s) on the site for various tree species.

Another source of information on the characteristics of the planting site--particularly if you acquired the site only recently--is local expertise. Talk to your neighbors, local Soil Conservation Service and other agricultural extension personnel, and the county or parish forester. These people may know of changes in flooding patterns (due to drainage projects, etc.) that are not covered in the soil survey. They may also have experience with other reforestation projects in the area and can relate any problems that were encountered.

Choosing the Species
Proper tree species selection is critical, since it will greatly affect the chances for successful reforestation. You should base your selection of tree species on several factors, including which species are capable of growing on the site, the availability of planting stock, and your personal objectives for reforestation.

The soil survey and local experts referred to above can help you with the question of which species will grow on your site. The county or parish forester is often a good source of information on the availability of planting stock and can also provide information on local markets for timber, pulpwood, and other forest products. The final choice of species, however, depends on you and the specific wildlife species you want to favor, and whether you also want to produce a valuable crop of timber. To help get you started, characteristics of some of the most commonly planted tree species are presented in Appendix A.

In most of the reforestation projects that have been carried out In the Lower Mississippi Valley, the emphasis has been placed on planting hard mast-producing species, particularly oaks and sweet pecan. These species are generally believed to have the greatest value to the most widely desired types of wildlife--deer, turkey, squirrel, and waterfowl. It is also widely believed that the lighter-seeded species, such as ash, elm, sweetgum, and sycamore, will establish themselves on the site on their own, since they are easily dispersed by wind or water. Although this approach to reforestation appears to be successful, you should not depend on the ligher-seeded species to always establish themselves on their own.

A tract of forest that contains many types of both hard and soft mast-producing trees is probably valuable to more species of wildlife than a stand heavily dominated by two or three hard mast-producing species since not all species eat hard mast, and also because it provides a measure of insurance for those years when hard mast production is poor. Therefore, we recommend that you also plant at least one or two species in addition to the hard mast-producers; especially if your planting site does not flood very often and is more than about 100 yards from a stand of mature forest that can act as a seed source.

Choosing the Planting Method
The two major planting methods are direct seeding and planting seedlings. Both can be done either by hand or with machines and are described in detail later in this bulletin. Direct seeding is usually less expensive than planting seedlings, though this will depend on factors such as the price of seed and labor and the availability of suitable machinery. Typical costs of direct seeding in 1989 were about $40-$6o per acre, while planting seedlings costs roughly twice as much. On the other hand, planting seedlings may result in faster initial establishment of a forest. You should give each method careful consideration in the planning stage because they will affect the type of planting stock you will need, and you should by to ensure that your desired stock will be available as early as possible.


SITE PREPARATION

The main purpose of site preparation is to create suitable growing conditions for free seed or seedlings. Another purpose in some cases is to create improved conditions that allow for use of mechanical planting equipment. Site preparation is not always necessary, but we do recommend it if the area to be planted has a plowpan or otherwise compacted soils or if the site has extensive weed cover.

Regardless of whether you reforest by direct seeding or planting seedlings, you will probably prepare your site by disking. If the site has a substantial cover of weeds, disking is helpful because it reduces the amount of competing vegetation, and by reducing the amount of weeds, it reduces the number of small rodents. High rodent populations are especially troublesome if direct seeding is planned.

Ideally, you should disk no more than 2 months prior to planting or seeding. However, disking may need to be done somewhat earlier if you plan mid to late winter or early spring planting and if flooding is a possibility. Two passes with the disk plow or barrow should be made, and disking should be to a depth of at least 6 inches, but preferably 8-15 inches.

In some cases, you may find burning or sub-soiling useful in preparing your site. Burning alone may be adequate on a field that has been fallow for a couple of years and does not have a plowpan. Sub-soiling may be needed on heavily compacted or otherwise degraded sites, but is rarely necessary on old agricultural fields.

Fertilization may increase the growth of some species planted on old field and other disturbed sites and therefore is occasionally done prior to planting. If you want to maximize growth of your planted trees, we recommend that you first get a soil test done, particularly for nitrogen and phosphorus levels. You should be aware, however, that while fertilization may increase growth, the increase may not be great enough to justify the costs from a timber production perspective.


DIRECT SEEDING

Direct seeding is becoming a widely used method of reforestation in the Lower Mississippi Valley. The primary advantage of direct seeding is its lower cost. Another advantage is that it allows tree roots to develop naturally without the disturbance caused by cutting roots and removing seedlings growing in a nursery.

A disadvantage of direct seeding is that it usually results in slower initial development of the forest. Also, a major limitation of direct seeding is that it is only reliable for oaks and to a lesser degree other large seeded species such as sweet pecan. The smaller seeds of many other bottomland species are much more susceptible to heat and dry soil conditions and, because they must be planted nearer the surface, are also more susceptible to bird and rodent predation. The procedures described in this section therefore should only be attempted for large-seeded species.

Obtaining Seed
Seed can be obtained either commercially or by collecting it on your own. We have listed a few commercial sources of seed in Appendix B, but your county or parish forester may be aware of smaller suppliers operating in your vicinity. Seed may be in short supply, so it is important that you place your order as early as possible if you plan to buy it.

If you decide to buy seed from a large supplier, you should request seed collected from sites as close as possible to your land. This seed is likely to be better adapted to your own site than seed collected from more distant areas. Ideally, seed should be obtained from sources no more than 150 miles from where you intend to plant. Also, you should ask the supplier to estimate how much of the seed is viable. Viability should be at least 80 percent; if it is less, you will have to compensate by planting more seed than we recommend in the “Depth of Sowing and Spacing” section.

If you are planning to collect your own seed, you should begin as soon as it matures, although you need to be aware that the very first seeds to fall are often not viable. The most common method of seed collection is simply to gather seed that has fallen to the ground and temporarily store it in a bucket, canvas bag, or other container. Plastic bags or other non-permeable containers should not be used for collection since they may cause overheating of the seed.

Assuming that there is a fairly good crop of seed on the ground, it is usually possible for one person to pick up from 8 to 10 pounds per hour. It is occasionally possible to speed up collection by shaking large amounts of seed out of trees onto a tarp, or by collecting seed from trees felled in logging operations.

If you are collecting acorns, the next step after collection should be the “float test.” The float test helps eliminate unsound (floating) acorns; it works for every species of oak except overcup, which floats even when sound. To test, place the acorns In a large container of water, stir them a couple of times, and skim off the floating acorns and other material. You should then completely drain the water.

Seed Storage
After collection, place red oak acorns (such as Nuttall, cherrybark, water, and willow oaks) and other large seeds in 4-6 mil thick polyethylene bags, tie the bags shut, and put them in cold storage (35 to 40 °F). These species can be stored successfully for at least 3 years. White oak acorns (such as overcup and swamp chestnut oaks) can also be stored in this manner, but only for a few months. You should try to plant white oaks within a month or two after collection rather than store them for an extended period.

If cold storage is unavailable, you can store seed over winter by burying them 1-2 feet underground, either in 4-6 mil polyethylene bags or loose. Under no circumstances should you leave seed in a warm, dry location for more than a couple of hours. If polyethylene bags are unavailable and you do not intend to store seed for longer than one winter, you can use burlap bags.

Timing of Direct Seeding
The most common times for direct seeding are fall, spring, and early summer. Oak acorns (and probably other large seeded species) may also be sown successfully at other times of the year, although the period of July through September is not recommended. The relative flexibility of timing is an important advantage of direct seeding; you can plant when you are not busy with other farm operations or wait until soil conditions are just right.

Depth of Sowing and Spacing
Acorns can be sown successfully at a depth of between 2 and 6 inches. Sowing 2-3 inches deep usually results in better germination and survival than sowing at 4-6 inches, but sowing deeper may pay off in situations where there are many rodents or the soil surface is subject to drying out completely.

Experience has shown that you can expect about 1 out of 4 acorns sown on old fields to produce a tree still growing well after 10 years. If you are sowing only acorns and hope that other types of trees will become established on the site naturally, you should sow as few as 800-1,000, and no more than 1,200-1,800 acorns per acre. This will produce from around 200 to 400 oak trees per acre after 10 years, which should allow some (though not much) growing space for other trees. Even at these densities some thinning of oaks may eventually be required.

Spacing for sowing 1,000 acorns per acre should range from 4.5 by 10 feet to 3 by 15 feet. Spacing for sowing 1,500 acorns per acre should range from 3 by 10 feet to 2 by 15 feet. If you want to avoid the eventual appearance of a plantation, with neat rows of trees, you can plant in wavy lines or even at random, as long as you allow enough growing space around each seed.

Hand Sowing
Direct seeding can be readily accomplished by hand methods. These can be as simple as using a slick or metal bar to make a hole, placing the seed in by hand, and closing the hole with your foot. A hand tool such as the one in Figure 9 can make the job easier by avoiding the need to bend over to put the acorns in the holes, and also can be constructed so as to ensure a uniform planting depth.

On a relatively clean, flat site, with favorable soil moisture conditions, a single planter should be able to sow around 7 or 8 acres per day using the hand methods described above. This amount can vary substantially, however, depending on such factors as the experience and physical condition of the planter, the depth of sowing, the distance the planter has to hand carry seed before being able to start planting, and the actual site conditions.

Machine Sowing
On old field sites under proper soil conditions, machine sowing works very well. A soybean or other type of planter can often be modified to allow for sowing acorns. Using the planter on a prepared site with good soil moisture conditions, three people can sow 40-60 acres per day. Rather than spending time and money modifying a planter on your own, you may be able to rent or barrow one. Your county or parish forester may know of planters available in your general area.


PLANTING SEEDLINGS

Planting tree seedlings is an old, well-established method of reforestation. When it is done correctly, the chances for successful establishment of a forest plantation are very high. If the planting is done incorrectly or carelessly, however, you are likely to end up with an expensive failure. The keys to successful initial establishment of tree seedlings, in addition to selection of the appropriate species for the site, are obtaining good quality seedlings, proper pre-planting care of the seedlings, and proper planting technique.

Obtaining Seedlings
The primary sources of tree seedlings are State forestry organizations and private nurseries (see Appendix B). Growing your own seedlings will rarely be cost effective and is only recommended for commercial operations.
The seedlings you will get from most of these nurseries will be bare-rooted, which means the seedlings have been separated from the soil they were growing in at the nursery. Bare-rooted seedlings are less expensive than seedlings in containers, lighter, easier to transport, and easier to plant.

In contrast to pine seedlings, which are usually planted while quite small, the hardwood or cypress seedlings you select should be good-sized and sturdy. Seedlings should have a top length of at least 18 inches. The diameter of the root collar (the part of the root just below ground level) should be at least 3/8 inch. The roots should be well-developed, and pruned to a length of about 8 inches, since this makes planting easier.

Handling Seedlings
While bare-rooted seedlings have the advantages mentioned above, they require careful handling. The most important thing to keep in mind is that the roots are very vulnerable, and if they die the seedling dies.

When you get seedlings from a nursery, they will generally be wrapped up in bundles of 50-200. If you are not going to plant them immediately, you should place the seedlings (still wrapped) in a cool, dark place--ideally in a cold storage unit. A barn, shed, or dense shade will do for a few days, as long as the roots are not allowed to freeze or dry out.

You should take only as many seedlings to the field as you intend to plant in a day. Take the seedlings out of the nursery-supplied bag and plant them immediately, or transfer small groups of seedlings to a bucket or planting bag containing moist sphagnum or peat moss. You should never carry a group of seedlings in your hand while planting because their roots will be exposed to the air and sun, and they can dry out very quickly.

Timing of Planting
The best time to plant bare-rooted seedlings is while they are dormant and when the soil is moist. Generally, planting conditions are most suitable in the Lower Mississippi Valley from January through about mid-March. Planting can be done into May if the seedlings are kept in cold storage (and therefore dormant) until planting. The ideal planting weather is cloudy and cool.

The most frequent limitations on planting during this season are excessive cold (planting should not be done in sub-freezing temperatures) and flooding of the site. The more flood-tolerant species can be planted in shallow water, but the job is much easier if the soil is moist but not flooded.

Spacing
If your goal is reforestation primarily for wildlife, you do not need to plant on spacings of 10 by 10 feet or less, which are frequently used for timber production. Spacings of 12 by 12, 15 by 15, or even 20 by 20 feet may meet your objectives and will do so at less cost. The number of seedlings you need for planting an acre at 10 by 10 foot spacing is 437; at 15 by 15 foot spacing you will need 194; and at 20 by 20 foot spacing you will need only 109.

Hand Planting
You can hand plant tree seedlings using a dibble bar or sharpshooter shovel. The technique for use with these tools is shown in Figure 14. It is important that the roots be placed in the hole so that they can spread out somewhat naturally; they should not be twisted, balled up, or bent. Moist soil should then be packed firmly around the roots.

Planting a tree by hand is a simple task, but nevertheless it is often done incorrectly. If you have a crew of inexperienced tree planters, you should take the time to demonstrate clearly the proper way to plant. Also, you should keep an eye on the crew to make sure they don’t get careless as the day wears on and they begin to get tired.

Seedlings should be planted with their root collars just below the ground surface (Figure 15a). Perhaps the most frequent planting mistake is planting the seedling either too deeply or, more commonly, not deep enough (Figures 15b and c). Another common mistake is digging a hole too shallow for proper placement of the roots. In such a case the roots may become bent upwards, or ‘J-rooted” (Figure 15d), which can result in the roots not penetrating deeply enough into the soil to protect the tree from windthrow or droughts. A third mistake is leaving art air pocket near the roots after closing the hole (Figure 15e), which may allow the roots to dry out.

You can expect one experienced person to plant roughly 600-800 seedlings per day on a relatively clean, flat site with moist soil. The rate can vary substantially, however, for the same reasons mentioned for direct seeding by hand, as well as depending on the size of the seedling being planted.

Machine Planting
Machine planters can speed up the planting job dramatically in soils other than heavy clays when other site conditions are favorable. An experienced crew of two or three can plant 4,000-10,000 seedlings a day with a planting machine, and often survival will be better than that achieved by a large, less-experienced crew of hand planters.

The cost of mechanical planters will be prohibitive for most small reforestation projects, but you may be able to rent one or borrow one from someone in the area. We recommend that you ask your county or parish forester about the availability of such planters in your area.


POST-PLANTING OPERATIONS

After planting, you should closely monitor the initial establishment of the seed or seedlings. If there is going to be a problem with the planting project, it will most likely show up in the first couple of years. Outright failures and only partially successful planting projects occur occasionally. They most often result from extended post-planting dry periods, flooding coupled with high temperatures, poor planting practices, residual herbicides or herbicide drift from nearby aerial applications, poor quality seed or seedlings, or animal predation.

During the first few years you may think that not a single tree survived but if you look closely, you will probably be able to find many small seedlings nearly hidden in the dense ground cover. If you direct-seeded the site, you should give the seed ample time to germinate before determining the initial success of the project; some seed planted in early summer may not germinate until late summer, fall, or even the following spring.

Post-planting weed control (by disking, mowing, and/or use of herbicides) may speed up growth of the seedlings during the first few years and perhaps slightly increase survival, but the benefits will seldom justify the costs. Post-planting weed control may be most critical where a heavy cover of large grasses (e.g., Johnson grass) or woody vines develops. In general, weed control should be practiced sparingly, since it may actually reduce the short-term value of the site to some types of wildlife, such as rabbits and some songbirds that use the weeds as food or cover.

If you expect to do some burning near the reforested site or suspect a neighbor might, you should create a firelane around the site annually in early fall. In most cases you can make a firelane by disking. Every time that an extended dry period occurs, you should inspect your firelanes and maintain them if necessary.

There is little you can do cost-effectively to protect your newly planted seed or seedlings from animal predation. Domestic animals, birds, dear, rabbits, squirrels, raccoons, beavers, nutrias, and mice may all destroy seed or seedlings. Fencing can control domestic animals and good site preparation can reduce the number of rodents. The only case where protection of individual seedlings is justified is where there are large populations of beavers or nutrias, in which case a chicken wire or other type of predator guard is essential, especially for cypress plantings. Some loss and damage caused by animals should be expected and tolerated, especially if your main goal is to attract wildlife.

As long as survival remains satisfactory, you shouldn’t worry if your trees grow slowly at first. Most species of oak, for example, only grow 1-2 feet per year for the first 5-7 years. After this stage, growth increases to around 2-3 feet per year. By the end of 10 years, your trees should be anywhere from 15 to 25 or more feet tall--and you’ll have a valuable, productive forest.