How can you manage your forests if you don’t know how much you have? For years that has been the challenge facing both the Conservation Department, which owns and manages nearly 600,000 acres of forest land, and Missouri’s private landowners, who own the lion’s share of the state’s forests, more than 11 million acres.
To help Missouri make wise choices, the U.S. Forest Service and the Conservation Department have teamed up to inventory and monitor the state’s forests.
Crews of foresters are now measuring and counting trees on private, state and federal land. Because it would be impractical to measure every tree in Missouri, researchers have developed a random sampling scheme of plots scattered across the state. Some crews inventory tree species, size and growth on each of the plots. Other crews measure indicators of forest health, such as crown dieback, insect and disease damage and tree mortality, on selected plots.
Foresters also visit all of Missouri’s sawmills to determine just how much wood is being harvested from our forests and where it ends up.
But forests and trees also grow in Missouri’s towns and cities. Indeed, for most Missourians the trees that line our streets and shade our local parks are the most important and valuable. The Conservation Department’s urban foresters periodically survey street trees in much the same way that more traditional foresters monitor the trees deep in our forests.
To get an accurate picture of what is happening in the state, the crews measure trees on both public and private land and in all forest types. The foresters always contact landowners to explain the purpose of the survey and to obtain permission to enter private lands.
Most Missouri landowners are glad to help us all gain a better understanding of Missouri’s forests. The benefits of forests include recreation, wildlife habitat, clean air and water and forest products. A complete forest inventory gives landowners and managers another tool to help ensure we will always have healthy, productive forests.
Crews completed the first statewide survey of forest land in 1947. Foresters also did surveys in 1959, 1972 and 1989. Inventory data quickly became outdated in the 12 to 17 years between periodic surveys. The 1998 US Farm Bill changed these from periodic to annual surveys. In 1999, the crews working in Missouri measured 20 percent of the 3,500 plots in the state. Each year they will measure a new 20 percent until all plots are completed after five years. Then, they’ll start again with the first 20 percent, repeating the cycle.
Crews will be at work in Missouri continuously and Missourians will no longer have to wait so many years for new forest information. A summary of the data will be compiled each year and a final report for Missouri will be produced every five years, when a cycle of the whole state has been completed.
When working in the forest, the first task for the Conservation Department and Forest Service crews is locating each plot. Plots are randomly scattered around the state on a grid system, and are marked on either satellite images or aerial photographs. Crews measured most of the plots in previous surveys, but it can take a long time walking in the woods to find them again!
Once on a plot, crews use a combination of high-tech equipment and good old-fashioned forestry tools to get the job done. For example, they measure tree diameter with a simple measuring tape, but the numbers are immediately entered into small handheld computers that have been designed to stand up to Missouri’s hot summers and cold winters.
The data is electronically "shipped" to the US Forest Services data processing center in St. Paul, Minn., where it is used to produce estimates of forest area, timber volume and growth, and to study changes in forest health. Forest inventory information is important to the foresters and landowners who manage Missouri’s constantly changing forest land. It provides the data they need for planning, protection and program development. The Conservation Department uses this information to advise private landowners and forest industries.
Just as important as knowing what our forests look like is knowing how they are being utilized, and whether that utilization is sustainable. Missouri is home to over 450 primary wood products producers - saw mills, charcoal mills, cooperage mills and many others. But we used to be home to many more. Over the years production has consolidated into larger and more modern mills.
Every three years, Conservation Department or consulting foresters visit all these mills and survey owners and operators on volume of wood used, preferred species, sourcing areas (the area of the state from which a mill buys timber) and production in the previous year. The results of these surveys are analyzed by the US Forest Service to produce an assessment of timber product output and use. The most recent results, published in 1999, cover the 1997 calendar year.
Missouri’s wood-using mills processed 140.5 million cubic feet of wood in 1997. This was an increase of 4 percent from 1994. Most of the wood came from Missouri’s forests, with only 6 percent coming from other states. The eastern Ozarks region of the state (including Bollinger, Butler, Carter, Crawford, Dent, Iron, Madison, Oregon, Reynolds, Ripley, St. Francis, Shannon, Washington and Wayne counties) accounted for over half of the total.
Almost all of the harvest was cut into saw logs, with charcoal, bolts, pulpwood and veneer logs making up only 10 percent of the total. Over 5,000 Missourians are directly employed by primary wood producers, and another 8,000 or more loggers, drivers and so on, indirectly owe their jobs to these mills.
Is this level of harvest and utilization sustainable? Thanks to all the work forestry crews have done on inventory plots, we can give a confident answer. Our forests are growing at a rate of at least 267 million cubic feet per year, so the harvest of 140.5 million cubic feet is easily sustainable in terms of volume. However, foresters and analysts will also have to keep a sharp eye on which species, which tree sizes and which regions the growth and harvesting impact.
The survey of wood producers not only tracks how much wood they use and what they produce, but the "leftovers" from their production processes. Despite improvements in saw technology, mills still produce over 2.1 million tons of "residues" a year, an increase of 6 percent since 1994. There are "coarse" residues, such as the slabs and edgings left when all possible boards have been sawed out of a log, and there are "fine" residues - sawdust - and there is bark.
Missouri’s mills have made strong progress in utilizing these parts of a tree, which used to be thought of as waste. Over 40 percent of the residues are now used to produce charcoal. Other uses include livestock bedding, mulch and fuel. Only 13 percent of the residues go unused.
Residents of Missouri’s towns and cities may appreciate the state’s forests, but the trees they live with every day are on their own streets, parks and playgrounds. The people who own and manage this resource (usually local governments, schools or organizations) need good information, too. Last year the Conservation Department helped Missouri become the first state to repeat American Forests’ survey of urban trees.
This program, begun in 1989, is designed to sample publicly owned trees in urban settings every 10 years. In 1999, we measured over 600 plots in 44 Missouri communities. Some changes in sample methodology make comparisons with 1989 data difficult (although the changes will give us a clearer picture next time, in 2009).
Still, the study has provided some clear results. In 1989, foresters found there were two empty planting spots, places where a tree would thrive, for every tree that was actually in the ground. By 1999, that ratio had gone down to one empty space for every tree already planted. In other words, our communities have done a great job planting trees over the last 10 years.
Most trees surveyed were of smaller size. It takes a long time to grow a big tree, and trees in urban settings often don’t live long enough (often less than 15 years) to reach the largest size class. Unfortunately, the average quality of the trees surveyed has declined slightly over the 10-year period. Perhaps this reflects the fact that planting trees is popular, but maintaining them is less glamorous.
The most popular urban trees were silver maple, pin oak, green ash, sugar maple, Siberian elm and sweetgum. But these six most poplar species made up only 37 percent of the total in 1999, while in 1989 they made up 53 percent of the trees surveyed. We’re seeing more diversity in our urban forests, and that is good both aesthetically and for the long term health of the resource. The more diverse our urban forests become, the more resistant they will be to diseases and pests.
Overall, the survey indicates that Missouri is home to 1.14 million urban street trees. Economists and foresters working with the International Society of Arboriculture (ISA) have even come up with a way to estimate how much those trees are worth to Missouri. The ISA formula factors in tree species, size and condition, as well as the location where the tree is planted and local prices.
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