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document Historic, archived Do not assume content reflects current scientific knowledge, policies, or practices. i North Central Research Station U.S. Department ofAgriculture - Forest Service 1992 Folwell Avenue Saint Paul, Minnesota 55108 2002 www.ncrs.fs.fed.us CONTENTS Results Area Volume Biomass . Forest Health Summary Appendix Inventory Methods . Sampling Procedures Phase 1 Phase 2 Literature Cited Table Titles Tables TheU.S.DepartmentofAgriculture(USDA)prohibitsdiscrimi- nationmallitsprogramsandactivitiesonthebasisofrace, color,nationalorigin,gender,religion,age,disability,political beliefs,sexualorientation,andmaritalorfamilystatus. (Not allprohibitedbasesapplytoallprograms.l Personswithdis- abilitieswhorequirealternativemeansforcommunicationof programinformation(Braille,largeprint,audiotape,etc.) shouldcontactUSDA'sTARGETCenterat(202)720-2600 (voiceandTDD). Tofileacomplaintofdiscrimination,wnteUSDA,Director, OfficeofCivilRights,Room326-W,WhittenBuilding, 14th andIndependenceAvenue.SW,Washington, DC 20250- 9410,orcall(202)720-5964(voiceorTDD). USDAisanequal opportunityproviderandemployer Printedonrecyclablepaper. Minnesota Forest Resources 2000 in The North Central Research Station's Forest 2000. Because ofthe limited number of AbouttheAuthors: Inventory andAnalysis Program (NCFIA) field plots measured, sampling errors are began fieldwork for the sixth forest inventory large at this point and data in this report David E. Haugen ofMinnesota's forest resources in 1999. This should be used with caution. Future is aforesterwith the inventory initiated the new annual inventory estimates that incorporate data in this Forest Inventoryand system in which one-fifth ofthe field plots report are subject to change when ensuing Analysis (FIA) unitatthe (considered one panel) in the State are annual inventories are completed and data North Central Research measured each year. A complete inventory compiled. Results presented are estimates Station, St. Paul, MN. consists ofmeasuring and compiling the data based on sampling techniques. As additional for all plots (or five panels). Once all panels annual inventories are completed, the Manfred E. Mielke have been measured, each panel will be precision ofthe estimates will increase and is a plant pathologistwith remeasured approximately every 5 years. For additional data will be released. the Forest Health example, in Minnesota, the plots in the 1999 Monitoring Program at panel will be remeasured in 2004. Reports ofprevious inventories ofMinnesota the St. Paul Field Office are dated 1936, 1953, 1962, 1977, and 1990. ofthe Northeastern Area In 2000, NCFIA continued the annual Data fromnew inventories are often compared State and Private inventory effort with the second panel ofthe with data fromearlier inventories to determine Forestry. sixth forest inventory. This sixth inventory of trends in forest resources. However, for the Minnesota's forest resources willbe completed comparisons to be valid, the procedures used in 2004. However, because eachyear's sample in the two inventories mustbe similar. As a tss>. is a systematic sample ofthe State's forest and result ofour ongoingefforts to improve the because timely information is needed about efficiency and reliability ofthe inventory, 1 — Minnesota's forest resources, estimates have several changes in procedures and definitions P" 13 been prepared from data gathered during the have occurred since the last Minnesota first 2 years ofthe inventory. Data presented inventory in 1990 (Miles et al. 1995). (See in this report represent 40 percent ofthe field appendix). Some ofthese changes make it plots (or two panels) for a complete inventory inappropnate to directly compare portions of and are a combination ofthe firstyear's panel the 2000 data with those published for 1990. from 1999 and the second year's panel from 1 RESULTS a slight increase of3 percent between 1990 and 2000, going from 14.7 million acres in Area 1990 to 15.1 million acres in 2000 (fig. 1). The total land area ofMinnesota is 50.9 In 2000, over 91 percent ofall forest lands in million acres (Miles etal. 1995), ofwhich 32 Minnesota were classified as timberland. The percent or 16.5 million acres are forested. increase in timberland area can be attributed Forest land area remained relatively in part to land conversion ofpasture and unchanged between 1990 and 2000, estimated croplands through both natural processes and at 16.6 million acres in 1990 and 16.5 million human intervention (tree planting and wildfire acres in 2000. Analysis ofthe 1990 periodic control) and m part to new forest lands that inventory measurements and the 1999 -2000 had been partially covered with trees but that annual inventory measurements indicates that did not have sufficient tree cover to qualify as this slight decrease in estimated total area of forest land in the previous inventory. forest land may be a result ofhigh sampling errors associated with a partial inventory The aspen-birch forest type, with over 6.7 rather than an actual loss offorest land million acres oftimberland, is the dominant between the two inventories (Hansen et al. forest type in the State (fig. 2) and is an 2001). Assucceeding annual inventories are important resource for Minnesota's forest completed, samplingerrors will decrease, industries. The spruce-fir forest type, with resulting in increased precision ofthe over 3.0 million acres oftimberland, makes up estimates and a more reliable picture ofreality. over three-quarters ofall conifer forest land Timberland, a subset offorest land that is area in the State. Between inventories, capable ofgrowing trees at a rate ofat least 20 hardwood forest types increased from 10.2 cubic feet per acre peryearofnet growth and million acres in 1990 tojust over 11.2 million that is not restricted from harvesting, showed acres in 2000, while conifer forest types 25,000 20,000 § 15,000 (0 -a c | 10,000 5,000 -I 1936 1953 1962 1977 990 2000 Inventory year — Figure 7. Area of timberlandin Minnesota byinventory year. 1990 2000 Aspen/Birch Maple/Beech/Birch Q. 3 o o> Elm/Ash/Cottonwood <aD > Oak/Hickory 55 Spruce/Fir White/Red/Jack Pine 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 Thousand acres — Figure2. Area oftimberlandin Minnesota in 1990and2000by forest type. decreased from4.4 million acres in 1990 to land ownership between inventories remained 3.8 million acres in 2000. Hardwood forest constant at 7.2 million acres. Over 85 percent types, especially aspen, have replaced ofall private forest land is found in the softwood types on many sites (Leatherberry et hardwood forest types. cd. 1995). The area differences between inventory cycles show that forest species Timberland area in the smallest average stand- composition in Minnesota is changing. size class (commonly referred to as sapling/seedling-size stands, whichhave more Forest land in public ownership remained than halfoftheir total live tree stockingin relatively unchanged between inventones, at trees less than 5.0 inches at diameterat breast — 9.2 million acres in 2000 (fig. 3). More than height d.b.h.) increased by 20 percent three-quarters ofall conifer forest types are between inventories. This increase represented found on publicly owned land. Private forest a gain ofabout 900 thousand acres by 2000 6,000 6,500 7,000 7,500 I ,000 8,500 Thousand acres — Figure3. Area offorestlandin Minnesota byownercategory. (fig. 4). Mediumstands (commonlyreferred to there are volumes in noncommercial trees, as poletimber, stands with halfor more oftheir rotten trees, and rough trees that do not total live tree stocking in trees at least 5.0 qualify as growingstock but that are utilized inches in d.b.h.), rose from 5.3 million acres of forwood fiber and fuelwood and that make timberland in 1990 to over 5.5 million acres in important ecological contributions (such as for 2000. In 2000, large stands (commonly wildlife habitat, and soil and water protec- referred to as sawtimber, stands withhalfor tion). With the annualized inventorysystem more oftheir total live tree stockingin trees at and increased interest in FIA data from an least 9.0 inches d.b.h. for conifers or 11.0 ecological perspective, a greater focus has been inches d.b.h fordeciduous trees) actually placed on all live volume. In 2000, Minnesota decreased by more than 700 thousand acres. had almost 17.6 billion cubic feet ofall live In 2000, timberland area was comprised ofthe volume on its 16.5 million acres offorest land. following stand-size classes: sawtimber 27 This equates to an average ofmore than 1,066 percent, poletimber 37 percent, sapling/ cubic feet ofall live volume foreach forest seedling 35 percent, and nonstocked <1 land acre in Minnesota. Unfortunately, all live percent. For more information on how FIA volume is not readily available from the determines stand-size class, see Miles et al. historic inventories and thus comparisons over (1995). time consider only growing-stock volume. Volume The net volume ofgrowingstock on Historically volume has been reported as timberland in Minnesota was estimated at 14. either growingstock orsawtimber. However, billion cubic feet in 2000, which equates to Sawtimber gPoletimber g Sapling-seedling 9.000 _ 1,000 7,000 6,000 5,000 4,000 3,000 2,000 1,000 1962 1977 1990 2000 Inventoryyear — Figure4. Area oftimberlandin Minnesota bystand-sizeclass andinventoryyear.