Tree Planting Enterprises on Flood-Damaged Farmland
John Dwyer, Douglas Wallace and Frank Hershey
Associate Professor, The School of Natural Resources, University of Missouri, Columbia, Missouri; Forester, USDA Soil Conservation Service, Columbia, Missouri; Watershed Specialist, USDA Forest Service, Columbia, Missouri.
Introduction
In the aftermath of the Great Flood of 1993 eight Midwestern States lost agricultural crops valued at $1.4 billion on six million acres. Missouri was especially affected because 498 miles of the Missouri and 487 miles of the Mississippi Rivers flow through or adjacent to the State boundary.
Floodwater damage to agriculture land in the floodplains of the Missouri River left behind a landscape scoured by erosion and inundated with sand deposits. In Missouri, the Soil Conservation Service estimates the flood left 60 percent (455,171 acres) of the previously cropped Missouri River floodplain covered by sand. Over 91,000 acres had sand deposits which averaged 24 inches in depth: At this time accurate information is still not available on how many acres were so severely damaged that traditional reclamation is not physically nor economically feasible.
However, it is safe to say that many landowners and even communities are looking at the social, environmental, and economical aspects of new alternative uses for the floodplain and its river corridor.
Purpose
Today, I would like to talk with you about tree plantings as an enterprise, but not in the sense that this is an economic activity, but from the standpoint of a daring new initiative. Forest researchers in the early to mid-seventies (Dutrow et. al 1970; Porterfield 1975) conducted economic evaluations of short rotation woody crop systems. These studies concluded that while fast-grown tree plantings are economically viable, they still can not financially compete with soybean production. A recent study was commissioned by the Environmental Protection Agency and conducted by the Center for Agriculture and Rural Development at the University of Missouri. The purpose of this study was to perform an economic analysis of various alternative floodplain management scenarios. This study concluded that although short rotation woody crop systems (hybrid poplars) and hebaceous energy crops (such as switchgrass) had positive net present worths they could not compete with corn, soybeans, and wheat.
One of the shortcomings of this study was the failure to include the high costs of levee repair into the costs of crop production. Such exclusions beg the question: What social costs are people expected to pay for crop production in the floodplain? Another problem which exists is the paucity of data on yield and production costs for switchgrass and hybrid poplar production in the Midwest, especially on deep sands.
However, the authors of this study do conclude that there is evidence which suggests that short rotation woody crop systems and hebaceous energy crop species can be successfully grown in areas susceptible to flooding. They go on to point out that these crops can provide benefits such as riverbank stabilization and levee protection, but these benefits are not quantified.
Recent studies (Doan and Ranney 1994) from Oak Ridge National Laboratory suggest that "efforts are justified to thoroughly examine overall benefits and costs of planting flood-prone agricultural areas within the Mississippi River valley to energy crops to reduce damages and costs related to flooding. In the interim, the facts are these: the levees are repaired, or for the most part, will be repaired, and crop production will continue in the floodplains.
What role can tree plantings play in the restoration and recovery of these dynamic riverine systems? In the near term, the role is not the traditional one of displacing crop production with tree plantations either as short rotation woody crops for fuel energy or even some alternative building material product (i.e. panel board). Farmers do not buy into tree planting as an economic alternative per se because they feel as though they could never exercise a harvest alternative in the future even if they wanted too because of section 404 wetland regulations.
One successful example of a working waterbreak can be seen at Thompson Bend on the Mississippi River in Mississippi County, Missouri. These cottonwood plantings established on former row crop land have demonstrated important functions which have included debris screening, uniform sediment deposition and elimination of scour erosion.
In informal discussions with farmers who farm the floodplains along the Missouri River around Brunswick and McBaine, Missouri, it was learned that they feel as though the tree buffer can play a role in protecting the floodplains. Some farmers would hope that the narrow tree buffer along the Missouri River could be widened.
Economic Benefits
I have identified four economic benefits "savings" from planting trees between the mainstem levee and the river bank:
- There will be a reduction in levee failure. I am not saying that levees will not be
breached during floods. What I am saying is that levees will not be destroyed,
although there may some topwash and sidewash. Trees planted in a wide enough
corridor on the inside of the levee in areas of high energy such as a bend in the river
(where past experience has shown levee failure) can reduce the flow rate and
dissipate water energy.
The Corps estimates the current cost of new levee construction at $240,000 per mile. This cost includes the cost of fill material, seeding, mulching, drainage, rock surface, standard scraping and maintenance. In the area of Saline County, Missouri, this cost represents an average of $400.00 per acre.
- There will be a reduction and elimination of sand deposition on tillable ground
behind the levee. In places along the river between Brunswick, Missouri, and
McBaine, Missouri, there can be seen depositions of sand within the tree line along
the riverbank which is actually higher than the man-made levee. The cost of sand
removal is estimated at $1,100 per acre. However, I suspect this is an optimistic
estimate.
- There will be a reduction in the government funds expended for corn price supports.
Assuming a target price of $2.75 per bushel, and an average projected farm or
market price of $2.25 per bushel, then the deficiency payment is $2.75 - $2.25 =
$0.50 per bushel. Furthermore, assuming an established corn yield of 100 bushels
per acre, then the payment is $50.00 per acre (100 bushels per acre x $0.50 per
bushel deficiency payment).
- There are soil erosion control benefits arising from timber production. Findings from a recent study ~oweg, 1994) have shown that the average present value of social benefits per acre obtained through the conversion of erodible agricultural lands in Mississippi to pine plantations was a positive $138.94 at a 4% real discount rate. For lands in the floodplain we simply do not know what the actual savings from soil erosion reduction would be as a result of tree plantings.
Future Research
I will conclude my presentation by telling you about a research project which we have initiated along the Missouri River within the Eagle Bluff Wildlife Area. This 3,636-acre tract just southwest of Columbia, Missouri, is designed to be the largest cooperative project in the nation utilizing treated wastewater effluent for wetland management.
The area selected for the tree plantings lies approximately 400 feet east of the Missouri River bank and adjacent to a 3,000-foot break in the main levee. The purposes of this project are to determine if specially selected fast-growing tree species can be successfully established and grown in deep sand deposits. A longer term goal is to monitor changes in the development of the organic layer and chemical properties of the soil.
Tree species chosen for study will include; native pecan (Carya illinoensis, Wangenh.), sycamore (Platanus occidentalis L.), eastern cottonwood (Populus deltoides Bartr. ex Marsh. var. deltoides), river birch (Betula niqra L.), and silver maple (Acer saccharinum L.). Each species will be replicated in three plots in each block, and each species will be randomly assigned to a plot. Each plot is 72.0 by 90.0 feet and will contain 50 trees of each species planted on an 8.0- by 10.0-foot spacing. In addition to the five species, a control treatment will be assigned to each randomized complete block. In the control treatment the natural recruitment of trees and other woody vegetation will be monitored, and no artificial planting will be done.
In each plot individual tree survival will be monitored and mortality will be determined. In addition, the diameter and height of individual trees will be measured and recorded. Also, cost and production data will be recorded for all tree planting establishment and early culturing activities. Individual-tree growth and yield data will be analyzed using analysis of variance statistical methods.
At the research site rainfall will be monitored and recorded using a Tipping Bucket Rain Gauge and electronic Event Recorder. At the ends of each plot a plastic pipe will be installed in the soil. Soil moisture will be recorded at different depths using Time Domain Reflectrometry. These climatic and edaphic factors will be used to study the relationship between depth of soil moisture and tree survival.
I perceive the role of tree plantings to be an insurance policy taken out to protect valuable resources between the main levee and the river bank.
References
Doan, M. and J. Ranney. 1994. "Energy crops on flood-prone sites: a preliminary review." Unpublished. Oak Ridge National Laboratory. Oak Ridge, Tennessee. Dutrow, G.F., J.S. McKnight and S. Guttenberg. 1970. Investment Guide for cottonwood planters. USDA For. Serv. Res. Pap. SO-59, S. Forest Exp. Stn., New Orleans, LA. 15p.
Noweg, T.A. 1994. Timber production and soil erosion control benefits of the agricultural conservation program in Mississippi. Published Doctoral Dissertation. University of Missouri-Columbia. I 87p.
Porterfield, Richard L. 1975. Sawlogs or soybeans. Forest Farmer 34(l0):16.
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