Forest Wetland Area and the Forest Sector Economy in the U.S. South

This article reviews current data on forest wetlands and their economic contributions in the South, ranging from Texas to Virginia. Based on USDA Forest Service Forest Inventory and Analysis (FIA) data, the wetland category comprised 17.7% of timber land area on all private and public lands in the South. This included 4.25 million ha of hydric sites; 0.77 million ha mesic wet; 9.55 million ha mesic, with only seasonal access; for a total of 14.57 million ha. The Natural Resource Inventory (NRI) for 2012 on private lands estimated that there were 14.71 million ha forested wetlands, which comprised 17.7% of all forested private forest area. The 2015 National Land Cover Data for the South estimated that there were 17.8 million ha of woody wetlands, which comprised 8% to 12% of the southern land area, and there were also 4.45 million ha of emergent herbaceous sites. About 10% of the southern timber forest sector would be based on harvests from wetland forests economy ($455 million per year), while the 17.7% of wetland land area would provide a proportional share of the annual nontimber forest products ($44 million) and payments for ecosystem services ($134 million). Wetlands also provide important nontimber forest products, and ecosystem services, which are beginning to develop active private and public markets.

forest products economy, focusing on timber values and economic contributions, also including an overview of nontimber forest products values and direct ecosystem services payments that wetlands may contribute to the region. Determining the precise area of forest wetlands in the South is difficult, since it depends on dynamic changes in the actual biophysical extent of wetlands; the objectives and methods used by several different federal organizations to measure that extent; and changing national definitions, policies, and court decisions dictating the definition.
The key forested wetland area and economic questions stem from the forested (or bottomland) definition and area. Wetlands may depend on ecological characteristics; federal agency definitions of jurisdictional wetlands based on hydrology, soils, vegetation, and various types of stocks (inventory, sinks, or pools) and flows of goods or services. Wetlands may produce annual or periodic flows and harvests, market and nonmarket values and prices, timber, nontimber products, or ecological and environmental services. We examine three principal sources that provide wetlands definitions and estimates to bracket the likely area of forested wetlands in the South.
Then we summarize secondary data on the annual market value of timber harvests, the forest products industry economic contributions, sales of nontimber forest products, and direct market payments received for forest ecosystem services in the South. We did not consider indirect economic or multiplier effects of forest products industries, nontimber products, or nonmarket values of ecosystem services, which are more complex and imprecise valuation questions.

Forest Wetland Definition and Area
For here, we classify southern forests as those covering the 13 southern states ranging from Texas to Virginia (Figure 1). This includes 216.5 million hectares (535 million acres) of total land area; 99.2 million ha (245 million ac) of forest land; and 85.0 million ha (210 million ac) of timber land that could provide commercial timber harvests. Forest ownership includes 59.5 million ha (60%) private non-corporate, 26.3 million ha (27%) private corporate, and 13.35 million ha (13%) public owners (Oswalt et al., 2014).
A widely agreed upon definition of the term wetland has been absent since the neologism was adopted (see Tiner (2016) for a review of the term's history and current definitions). In part, a single definition has not been widely adopted because of the numerous aspects from which it might arise (e.g., ecology, soil science, hydrology, legal, jurisdictional). For example, a mud flat might satisfy wetland criteria for a soil scientist or hydrologist but not for an ecologist because mud flats are generally devoid of vegetation. The seemingly countless jurisdictional-specific definitions provided by Tiner (2016)   what constitutes a wetland . This definition has become increasingly important, since land that is classified as a "federal" wetland, whether on public or private land, is subject to varying levels of regulation, permits, and control of forest, agriculture, and development practices. In brief, Section 404 of the FWPCA/Clean Water Act definition of a wetland is that they are "Those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas." The FWPCA/Clean Water Act definition includes the three main criteria that are regarded as distinguishing wetlands from uplands (Tiner, 2016).
The typical three criteria for wetland determinations are:  Hydrology-recurrent soil saturation or inundation during the growing season, e.g. for 5% -12% of the period, or about 14 consecutive days  Hydrophytic plants-species that are adapted to life in saturated soils, e.g.
obligate species  Hydric soils-soils that formed under anaerobic and reducing conditions, e.g. mottled, smell like rotten eggs

Wetland Areas
Each of the three federal organizations that classify wetlands has derived somewhat different area estimates. We summarize the amount of forested wetland area estimates based on the USDA Forest Service Forest Inventory and Analysis (FIA) data, the USDA Soil Conservation Service National Resource Inventory (NRI) data, and the USDI Geological Survey National Land Cover Data (NLCD).
The FIA data for the South classes their forest plots that cover all ownerships with various characteristics that serve as proxies for wetlands. First, they class each site surveyed as a land type, such as the wetlands that consist of hydric sites, or wet flood plains/bottomlands. They also classify wetlands by operability class, with either year round water or seasonal access. The USDA Natural Resource Inventory (NRI) analysis estimates land classes on private lands. The National Land Cover Database provides a point estimate of woody wetlands, also covering all lands in the U.S.

USDA Forest Inventory and Analysis (FIA) Data
The Forest Service FIA data provides a comprehensive survey of forest areas in the United States (https://www.fia.fs.fed.us/tools-data/), with a number of breakdowns that can be used to classify forest areas as wet, providing a good proxy for those areas with formal federal wetlands designation. We obtained and screened the FIA data for the South to identify forests that would be likely to have the three key federal wetlands hydrology characteristics listed above, with forest vegetation management types as well, although soils data were not available.
The FIA survey crews categorize forest land data in management types based on land use classes-these classes may call even cut-over land as forests if they appear to be regenerating and coming back as forests in the future. There are various classes of forest land in timber land, with "forest" being the broadest-covering all lands covered at least 10% with trees, and having a minimum area of 1 acre (0.4 ha). Timber land is more relevant in determining market values of forest land, and reflects land that is capable of producing crops of industrial wood and not withdrawn (e.g., under a reserved or protected land designation) from timber utilization or administrative regulation (Oswalt et al., 2014 Natural pine had 0.75 million ha of mesic/seasonal access lands, or 5.8% of their management type. Pine plantation had 1.2 million ha of mesic/seasonal access sites-6.8% of their management type. The area of all three FIA data screens for forests ranging from hydric sites with year-round water to mesic sites with seasonal access totaled 14,615,975 ha, or 17.7% of all southern forests ( Figure 2). As expected, bottomland hardwoods dominated this total area, with 9.4 million ha, or 64% of the total wetland types, but it was not the only forest type with some type of wetland characteristics.
Upland hardwood forests had 1.76 million ha, or 12% of the total area in these three forest wetland types. Oak pine forests had 1.0 million ha, or 6.8% of the total in these three forest wetland types. Natural pine forests had 1.15 million ha, or 7.9% of the total in these three forest wetland types. Planted pine forests had 1.29 million ha, or 8.9% of the total in these three forest wetland types.
As a percentage of their total forest area by management type, bottomland forests had 75% classified in the three wetland phases. Upland forests had 6%; oak  So overall, note that not all bottomland hardwoods are likely to be wetlands, and that even upland forests and pine plantations are apt to have some areas with that vegetation and physiographic type that do include wetland areas based on hydrology. Figure 3 shows the mesic wet forest types-the largest pine wetland areas-for natural and planted pine by state as classified by FIA. In general, the data indicate that the South Central states seem to have a much greater area of pine forests that lie in mesic wet areas than the Southeast, with more than twice as much wet pine areas. This seems counterintuitive given the vast pine forests and wet areas from Georgia to North Carolina, so perhaps the field crews were more chary calling areas as wetlands in the eastern South than in the western South.

Southern Wetland Area, Private Lands, Natural Resource Inventory
The USDA Natural Resource Inventory (NRI) also measures land type as part of its periodic survey of private lands in the United States (https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/technical/nra/nri/).
For reference, in the U.S. South, private forests comprise 87% of all timber land (Oswalt et al., 2014). Cubbage & Flather (1993) examined wetlands status with NRI data previously, which we update here. The most recent data available are for 2012, which can be compared to the 1992 data, again spanning from Texas to Virginia (Table 2). As the table shows, the wetland area has been pretty consistent since the 1990s, and the strict federal no net loss of wetlands policy since then would suggest that was likely to continue in the 2000s as well, unless that policy is reversed or not enforced.  The NRI data indicate that there were 21.6 million ha of palustrine and estuarine wetlands in 2012; of that, 14.7 million ha (68%) were forested (Table 2).
Southern palustrine/estuarine wetlands would include inland, nontidal wetlands with trees, shrubs, and emergent vegetation as well as tidal wetlands with similar vegetation definitions. Some of the estuarine wetlands could include forest types, and some palustrine wetlands could include vegetation smaller than trees. Thus

Wetlands, National Land Cover Data
The National Land Cover Database (NLCD) (https://www.mrlc.gov/) maps land cover for the United States using Landsat satellite and other ancillary data (Homer et al., 2015). Forested wetlands are common and widely dispersed throughout the region based on NLCD maps (Table 3 and Figure 4). The figure class labels are Orange = urban; green = upland forest; purple = woody wetland (wet forest); cyan = emergent wetland; blue = water. The other classes (agriculture, grassland, shrubland, barren) are not colored.  Drawn from NLCD data base (https://www.mrlc.gov/). Note: 1 m 2 = 0.0001 ha; 10,000 m 2 = 1 ha; 1 ha = 2.47 ac. Open Journal of Forestry based on land cover, so cut-over forest may be identified as shrubland and grassland rather than the parcel's land use (e.g., forest). The NLCD classification includes four classes of urban development, three classes of upland forest, two classes of agriculture and wetland, and one class each for barren, water, shrubland, and grassland (https://www.mrlc.gov/nlcd11_leg.php). The NLCD data base provides a larger estimate of forested wetlands in the South than the FIA data did, at 17.9 million ha (44.1 million ac) for the same 13 states. However, the NLCD data indicate that Texas has the largest forest area in the South, which must include a lot of area that is not timber land by FIA definitions, and Oklahoma is also one of the largest forested wetland states, which certainly differs from FIA. If one were to remove these optimistic data points, the NLCD forest wetland area would decrease to 15.8 million ha (39.1 million ac), which seems more aligned with the other two federal government data sources. This discrepancy between NLCD and FIA/NRI is also notable when one measures the share of forest land in the South. Without Texas and Oklahoma, the NLCD would indicate that forest cover types comprise 52% of the South; which is similar to FIA. With Texas and Oklahoma, which have vast areas of rangelands, forests comprise only 37% of all land covers, which seems unrepresentative of the rest of the forested South from east Texas to Virginia. However, the NLCD data do seem to be more consistent than the FIA data with what one would expect across the South by state, with a fairly logical distribution of wetland types by size of state and proximity to wet coasts, regardless if they are in the West South or East South ( Figure 5).

Forest Products, Nontimber Products, and Ecosystem Service Payments
Timber harvests and wood based manufacturing are a major part of the southern economies, and wetlands forests contribute a modest share of those harvests and value added. In addition, forests are producing an increasing amount of nontimber forest products, and provide a variety of ecosystem services, and some of those may generate direct payments to monetize those previously nonmarket values. This section summarizes aggregate southern timber, manufacturing, nontimber, and ecosystem service payments that are available in the literature. As noted before, we only summarized data on the annual market value of timber harvests, the forest products industry economic contributions, sales of nontimber forest products, and direct market payments received for forest ecosystem services in the South. We did not consider indirect or multiplier effects of forest products industries, nontimber products, or nonmarket values of ecosystem services. Each of these broader effects of forest economies are important, but become much more complex and unique to different regions and different methods of estimation, and indeed considerable scientific debate in the case of ecosystem services. Thus we focused strictly on an "apple-to-apple" comparison of the measurable market sales revenue or direct payments that actually were received and estimated for southern wetland forests.

Forest Products Economic Contributions
As One could calculate a growth to removals ratio for these timber volumes as 1.6:1 for pine and 1.92 for hardwoods. Bottomland hardwoods actually have a lower growth to removal ration, at 1.51:1, but are thus still growing 50% more volume each year than is being removed. Softwoods had an inventory to removal ratio for these timber volumes as 25:1, and it was 82:1 for hardwoods. This can be interpreted as the implicit rotation age of 25 and 82 years without growth for the two major species groups. Thus both softwoods and hardwoods had annual growth greater than annual removals, which would infer that there is a large supply of timber in the foreseeable future.
It also is worth noting that lowland hardwoods had a very high concentration of volumes in the oldest age classes of 50 years or older ( Figure 6), with about half the total area. For the lowland hardwood age class in the South, there were 14.3 million acres (5.79 million ha) in the 0 -50 year old age classes, and 12.7  million acres (5.12 million ha) in the 50+ age class (47% of all lowland hardwoods). This indicates a surprising lack of diversity on lowland hardwood stands. Upland hardwoods were actually worse, with 53% on the oldest age class of 50+ years. In contrast, planted pines had no reported volumes in the 46 -50 or 50+ age classes. Natural pines had 24% older than 50 years of age; oak-pine had 36%.
The forest products industry economic contributions included those from forests, timber production, and processing of solid wood, wood furniture, and paper products. Employment in all these sectors in 2009 totaled 470,000 persons, which was 0.84% of the South total employment. Their gross industrial output was $133 billion, 1.62% of the South total. Wages and salaries were $26 billion; 0.96% South Total. Total value added was $43 billion, 0.98% South total (Dahal et al., 2015).
Economic contributions were similar in 2011 although total direct employment was still 473,000 persons, and value added was $46 billion. Indirect effects from forest products would almost double those, with 1 million employees and $87 billion of value added. As shown in Figure 7, the forest products sector contributions to each state total economy ranged from a low of 0.7% in Florida to about 5% in Arkansas (Brandeis & Hodges, 2015).
One also can make rough estimates of the share of bottomland hardwoods as a  . Percentage of total value added contributed by the forest sector to the southern states gross regional product, 2011 (Brandeis & Hodges, 2015).
billion cubic feet in the South would be $1.62 billion, and softwood price for 5.3 billion cubic feet would be $3.18 billion.

Nontimber Forest Products and Ecosystem Services
Forests also provide nontimber forest products and economic contributions that receive payments directly for the products or to service providers who facilitate the activities. These include hunting and fishing of game; viewing of wildlife; and watching of local and migratory birds. Tourism and recreation such as canoeing, eco/tourism, and beach recreation and shore protection generate large incomes. Educational forest uses for elementary to secondary schools, youth groups, environmental education, and citizen science efforts also generate for-

Timber versus Nontimber Prices Plus Ecosystem Payments
Southern forests comprise about 40% of U.S. total forests; bottomland forest areas are about 15% of southern forests; and bottomland forest harvests are about 9.55% of southern forests. The harvest of nonwood forest products is likely to follow this proportional share, as are the payments for environmental services. These statistics can be used to compute rough total values for economic payments, as summarized in Table 6. The data in Table 6 provide a fascinating snapshot of approximate values of timber, forest products, nontimber, and ecosystem service payments in the U.S and the South. All southern forest products shipments in 2006 were valued at $160 billion, and relative bottomland forest share of these based on their timber harvest would be $16 billion. The value added-the best estimate of a sector's share of the total regional gross product that does not double count any input costs-would be $43 billion for forest products, and $4.3 billion for the bottomland hardwood contribution to that total.
The value of the annual timber harvest in the United States was calculated as $7.7 billion; the South's would be $4.8 billion, and the bottomland hardwood share $455 million. This could be compared with nonwood forest products prices for the U.S. of $361 million; $144 million for the South, and $25 million for Notes: Forest products shipments and value added from Forest2Market (2016), Brandeis & Hodges (2015) and Dahal et al. (2015). 2011 national timber removals (harvests) were 8.3 billion ft 3 of softwood; 4.5 billion ft 3 of hardwoods; 12.9 billion ft 3 total. Southern timber removals (harvests) were 5.3 billion ft 3 of softwood; 2.7 billion ft 3 of hardwoods; 8.0 billion ft 3 total (Oswalt et al., 2014). Timber values calculated as mix of 50% sawtimber and 50% pulpwood, at a blended price of $0.60 per cubic foot for stumpage for both softwood and hardwood species groups (Timber Mart-South, 2016). Southern timber land was 40% of U.S. timber land (Oswalt et al., 2014 which one would assume to be more prevalent in wetlands, but these might be offset by higher shares of goods such as Christmas trees from mountain or at least Piedmont physiographic regions, so making item by item adjustments to the broad nontimber products and ecosystem payments seems untenable.

Discussion and Conclusions
This review provides a summary of wetland forest areas, values, and economic contributions in the South. Obtaining universally agreed on data on wetland areas in the South is difficult, because the federal definition of wetlands has been fluid over time, and even if it were agreed on widely, one still needs to go to the field to determine whether a specific site and piece of property is indeed a wet- Of the data sets, the USDA FS FIA site characteristics indicate that wetlands types would be about 17.7% of timber land, including 4.25 million ha of hydric sites, 0.77 million ha mesic wet, and 9.55 million ha mesic, seasonal access, for 14.6 million ha in total. These FIA wetland breakdowns by Forest Management Type would be 9.4 million ha bottomland hardwood; 1.7 million ha upland hardwood; 1.0 million ha oak-pine; 1.1 million ha natural pine; and 1.3 million ha pine plantation.
The literature on the aggregate economic contributions of the forest products industry-forests, timber production, and processing of solid wood, wood furniture, and paper products-provided substantial estimates in terms of actual people and dollars involved, but it was still a relatively small share of the total southern economy. Quite simply, all modern economies are broad and complex, with many important sectors, so no one sector can dominate most regions. Forest products based employment was 470,000 persons, equal to 0.84% of South Total. Gross output was $133 billion, consisting of 1.62% of South Total. Wages and salaries were $26 billion; 0.96% of the South Total. And the total value added of $43 billion was 0.98% South Total. However, in several states, forest products accounted for up to 5% of the state economy, and was the largest contributor to value added in many southern states.
Based on the FIA data, one can derive the share of wetland forests as a component of total forest products economy, nontimber goods, and ecosystem services. Bottomland hardwood timber land consists of 12.6 million ha-15% of the South, although not all of these are wetlands. However, the addition of other forest management types increases the estimated hydric and mesic wet forest areas of the South to 14.6 million ha, which is about equal to the NRI estimate of southern wetlands, and equals 17.7% of all southern timber land.
Timber removal volumes based on the FIA data were less on southern hardwood forests (34%) and on bottomland hardwoods (28% of all hardwoods) than on pine types (66%), so we estimate that at least 9.5% of the total southern timber harvest volume is obtained from wetlands given the 12.6 million ha of bottomland hardwood types, and this estimate would increase to more than 10% with the additions of 2 million ha in the other forest management types. In practice, only 9.4 million ha of bottomland hardwoods are classed as wetlands, and 5.2 million ha of other forest management types make up the difference for the 14.6 million ha wetland total of all FIA forest management types. This would increase the wetland timber harvests to slightly more than 10% of the total. These derivations then indicate that at least 10% of the southern timber-based forest products economy is derived from wetland forests based on the value of its harvests, while almost 18% of the southern nontimber forest products and payments for ecosystem services stem from wetland forests based on the share of area that they include.
The relative values of timber stumpage of $455 million from wetland forests versus $178 million for nontimber products and payments for ecosystem servic- There are also much greater values that have been estimated for the nonmarket benefits of ecosystem services, in addition to the direct payments reported here. These include benefits such as watershed and soil protection, water filtering, climate control, carbon storage, nutrient cycling, soil formation, biodiversity, rare habitats, landscape, corridors, recreation, aesthetic, cultural, and spiritual values. Nonmarket valuation tries to estimate these environmental and social values, using revealed preference approaches such travel costs, hedonic pricing, ecosystem production and cost functions; or using stated preferences methods such as contingent valuation method (CVM), stated choice, or conjoint analysis; or by benefits transfer methods (Sills et al., 2017).
Some studies have examined the nonmarket values of forested wetlands, and indeed provided quite large theoretical prices for forest wetlands. For example, Jenkins et al. (2011) estimated the economic effects of Wetlands Reserve Program using site and region level measurements and ecosystem process models. They found that greenhouse gas mitigation was worth $171 to $222 per ha per year; nitrogen fixation was worth $1486 per ha per year; waterfowl recreation was worth $16 per ha per year. These values were contrasted with the land value of conventional timber management, which had actual values of only about $70 per ha per year. Of course, the timber benefits could be received as cash payments, and ecosystem benefits were social values, not cash. Moore et al. (2011;cited in Mahaffey & Evans 2016) estimated that forested wetlands had annual values of $11,600 per ha for flood control, $8600 per ha for pollution treatment, and $2850 per ha for water supply value in Georgia.
The preceding two large estimates of southern wetlands values in the refereed and gray literature, respectively, are promising, but still do not mean that those values will result in commensurate direct payments to landowners in the foreseeable future. Thus in this paper, we focused on comparing the specific market transactions-either through private markets or government payments-to compare the actual wetland economy in the South. Timber income from stumpage sales in southern bottomland forests provided the largest cash receipts as calculated here. These incomes calculated were followed by the direct government or market payments received for environmental services, at about 30% of the calculated timber income. Nontimber forest products sales were less, at about 10% of the estimated timber receipts. Wetland forests also provide a wealth of nonmarket, non-paid ecosystem services, which have ecological and social values, but have not been monetized to date. They may indeed be far The potential large areas and high values of wetlands are indeed the premise on which much of the Clean Water Act protection for wetlands is based. This paper does provide a review of current forest wetland areas and market values in the South. This should be useful in clarifying forest wetland areas and values for the region, and providing much better information for assessing trends and for discussing wetland forest policy options in the future.