Showing 21 – 30 of 53 resources

Examining the impact of seed production on sap sugar content

Sap flow is only part of what determines the total amount of syrup made (and how much money ends up in a syrup producer’s pocket). New research suggests sugar makers may be advised to look to their trees’ canopies as well as the weather forecast if they want to predict the tapping season.

Evaluation of Sugar Maple Dieback Trends in the Upper Great Lakes Region

Crown dieback and declines in tree health of sugar maple (Acer saccharum) have been reported on various land ownerships in the western Upper Great Lakes region in recent years (MDNR 2009, 2010, 2012). In some areas, the crown dieback has affected high-value crop trees. Historically, sugar maple dieback (fig. 10.1) has been reported more frequently in the eastern part of its range and has not been described on the same scale in the Great Lakes region since the 1950s and 1960s (Bal and others 2015, Millers and others 1989). As a result, fewer studies of canopy health of sugar maple exist in the Midwest than in the Eastern United States.

A Model of the Tapping Zone

A model that calculates the proportions of conductive and nonconductive wood in the tapping zone of a tree over time given user-input values for tree diameter and tapping practices.

Calcium and aluminum impacts on sugar maple physiology in a northern hardwood forest

Forests of northeastern North America have been exposed to anthropogenic acidic inputs for decades, resulting in altered cation relations and disruptions to associated physiological processes in multiple tree species, including sugar maple (Acer saccharum Marsh.). In the current study, the impacts of calcium (Ca) and aluminum (Al) additions on mature sugar maple physiology were evaluated at the Hubbard Brook Experimental Forest (Thornton, NH, USA) to assess remediation (Ca addition) or exacerbation (Al addition) of current acidified conditions. Fine root cation concentrations and membrane integrity, carbon (C) allocation, foliar cation concentrations and antioxidant activity, foliar response to a spring freezing event and reproductive ability (flowering, seed quantity, filled seed and seed germination) were evaluated for dominant sugar maple trees in a replicated plot study.

Effects of Acidic Deposition and Soil Acidification on Sugar Maple Trees in the Adirondack Mountains, New York

High levels of atmospheric sulfur (S) and nitrogen (N) deposition have substantially damaged ecosystems in the Adirondack Mountains of New York. Efforts to quantify damage have largely focused on aquatic effects2 However, limited recovery of surface water acid?base chemistry in response to large (>40%) decreases in S deposition over the past two to three decades has been attributed to depletion of soil calcium (Ca) and other base cations that may be ongoing despite declining acidic deposition. Availability of soil Ca has also been linked to changes in terrestrial faunal and vegetation communities in Adirondack hardwood forests.

Age, allocation and availability of nonstructural carbon in mature red maple trees

The allocation of nonstructural carbon (NSC) to growth, metabolism and storage remains poorly understood, but is critical for the prediction of stress tolerance and mortality. We used the radiocarbon (14C) Ôbomb spikeÕ as a tracer of substrate and age of carbon in stemwood NSC, CO2 emitted by stems, tree ring cellulose and stump sprouts regenerated followingharvesting in mature red maple trees. We addressed the following questions: which factors influence the age of stemwood NSC?; to what extent is stored vs new NSC used for metabolism and growth?; and, is older, stored NSC available for use?

Seasonal dynamics and age of stemwood nonstructural carbohydrates in temperate forest trees

Nonstructural carbohydrate reserves support tree metabolism and growth when current photosynthates are insufficient, offering resilience in times of stress. We monitored stemwood nonstructural carbohydrate (starch and sugars) concentrations of the dominant tree species at three sites in the northeastern United States. We estimated the mean age of the starch and sugars in a subset of trees using the radiocarbon (14C) bomb spike. With these data, we then tested different carbon (C) allocation schemes in a process-based model of forest C cycling.

Influence of experimental snow removal on root and canopy physiology of sugar maple trees in a northern hardwood forest

Due to projected increases in winter air temperatures in the northeastern USA over the next 100 years, the snowpack is expected to decrease in depth and duration, thereby increasing soil exposure to freezing air temperatures. To evaluate the potential physiological responses of sugar maple (Acer saccharum Marsh.) to a reduced snowpack, we measured root injury, foliar cation and carbohydrate concentrations, woody shoot carbohydrate levels, and terminal woody shoot lengths of trees in a snow manipulation experiment in New Hampshire, USA. Snow was removed from treatment plots for the first 6 weeks of winter for two consecutive years, resulting in lower soil temperatures to a depth of 50 cm for both winters compared to reference plots with an undisturbed snowpack.

Long-term impact of liming on growth and vigor of northern hardwoods

Sugar maple (Acer saccharum Marsh.) is a keystone species in the northern hardwood forest, and decline episodes have negatively affected the growth and health of sugar maple in portions of its range over the past 50+ years. Crown health, growth, survival, and flower and seed production of sugar maple were negatively affected by a widespread decline event in the mid-1980s on the unglaciated Allegheny Plateau in northern Pennsylvania. A long-term liming study was initiated in 1985 to evaluate responses to a one-time application of 22.4 MgáhaÐ1 of dolomitic limestone in four northern hardwood stands.

Sugar maple growth in relation to nutrition and stress in the northeastern United States

Sugar maple, Acer saccharum, decline disease is incited by multiple disturbance factors when imbalanced calcium (Ca), magnesium (Mg), and manganese (Mn) act as predisposing stressors. Our objective in this study was to determine whether factors affecting sugar maple health also affect growth as estimated by basal area increment (BAI). We used 76 northern hardwood stands in northern Pennsylvania, New York, Vermont, and New Hampshire, USA, and found that sugar maple growth was positively related to foliar concentrations of Ca and Mg and stand level estimates of sugar maple crown health during a high stress period from 1987 to 1996. Foliar nutrient threshold values for Ca, Mg, and Mn were used to analyze long-term BAI trends from 1937 to 1996. Significant (P <= 0.05) nutrient threshold-by-time interactions indicate changing growth in relation to nutrition during this period.