Influence of Nutrition and Stress on Sugar Maple at a Regional Scale

1. Influence of Nutrition and Stress on Sugar Maple at a Regional Scale Scott W. Bailey Richard A. Hallett Robert P. Long Stephen B. Horsley Philip M. Wargo USDA Forest Service, Northern Research Station

2. Sugar Maple Decline • Scattered, episodic occurrences • First documented in 1913 • Increasing frequency since 1960 • Throughout range (WI, ON, QC, VT, MA) • Recent declines in northern Pennsylvania

3. Symptoms of Declines • Reduced growth • Shoot and diameter • Shorter internodes produce tufted appearance • Premature fall coloration • Unusual levels of twig and branch dieback • Individual trees showing these symptoms are randomly dispersed in the stand.

4. Decline Disease Characteristics • Interaction of multiple causal factors • Abiotic and biotic factors • Gradual general deterioration, often ending in death of trees • Often poorly understood after Manion (1991) Tree Disease Concepts

5. Stress Factors 1. Predisposing factors Imbalanced Nutrition Calcium Magnesium Manganese (Aluminum)

6. Stress Factors 2. Inciting factors • Defoliating Insects • Drought • Soil Freezing • Winter Injury

7. Stress Factors 3. Contributing factors • Fungi (esp. Armillaria) • Borers • Viral infections

8. The Allegheny Problem 1994 survey showed 38,000 hectares with severe mortality on the Allegheny National Forest An additional 19,000 hectares with severe mortality were on state forests across the northern tier Sugar maple is the most severely impacted species with unusual mortality levels first noted in the early 1980’s

11. 30 Dead Basal Area % 20 10 0 3 Vigor Class 2 1 upper lower upper lower unglaciated glaciated

12. 2.0 Foliar N % 1.0 0.15 P 0.10 0.05 0.9 K 0.6 0.3 upper lower upper lower unglaciated glaciated

13. Foliar Ca % 1.0 0.5 0 0.10 Mg 0.05 0 0.2 Mn 0.1 0 upper lower upper lower unglaciated glaciated

14. Insect Defoliation • Between 1984 and 1996 eighty-six percent of the Allegheny National Forest received from 1 to 5 moderate to severe defoliations by: • Fall Cankerworm, elm spanworm, forest tent caterpillar, saddled prominent, gypsy moth and pear thrips.

15. 50 40 30 Dead Maple (% Basal Area) 20 10 0 0.05 0.10 0.15 Foliar Magnesium (%)

16. Vermont and New Hampshire Stands The additional stands were all glaciated and the till quality was variable. The range in nutrient status was similar to the stands in PA/NY. Generally lacked defoliation events during the past 20 years.

17. Foliar Nutrients ? 300 600 900 1200 1500 1800 2100 2400 2700 3000 2000 4300 6600 8900 11200 13500 15800 18100 20400 22700 25000 ? Will these low nutrient status stands that have NOT been stressed have poorer health? 5500 ppm PA/NY NH/VT 700 ppm PA/NY Calcium NH/VT 3300 Magnesium

18. 25% 20% 15% 25% Northern New England 10% 20% 5% Health Threshold Health Threshold 15% 0% 0 5000 10000 15000 20000 30000 25000 10% 5% 0% 0 500 1000 1500 2000 2500 3000 Sugar Maple Fine Twig Dieback vs. Foliar Mg and Ca Sugar Maple Dieback Plateau - mild defoliation Plateau - severe defoliation Foliar Mg (ppm) Sugar Maple Dieback Foliar Ca (ppm)

19. Putting it all together: Stress, Ca, Mg, and Dead Sugar Maple High Mg High Ca Low Ca 40% Low Defoliation Stress High Defoliation Stress 35% PA/NY NH/VT 30% 25% Dead Sugar Maple Basal Area 20% 15% 10% 5% 0% Low Mg • Defoliation stress does not impact SM mortality when nutrient thresholds are exceeded. • In addition SM mortality is not effected in low nutrient status stands when defoliation stress is low. • However when nutrient status is low AND trees are stressed, sugar maple mortality increases.

20. High Mg Low Mg High Ca Low Ca Putting it all together: Stress, Ca, Mg, and Fine Twig Dieback Low Defoliation Stress High Defoliation Stress 15% PA/NY NH/VT 10% Fine Twig Dieback 5% 0% • Fine twig dieback is a less severe health indicator than mortality. • Again, adequate nutrients result in good health regardless of stress. • However we see that poor nutrient status results in poorer health even when there is no defoliation stress.

21. Putting it all together: Manganese Toxicity Low Mn Low Mn High Mn Low Mn High Mn Although Mn is an essential nutrient, in high enough quantities it becomes toxic to sugar maple trees. 40% Low Defoliation Stress High Defoliation Stress 35% PA/NY NH/VT 30% 25% Dead Sugar Maple Basal Area 20% 15% • High Manganese and high stress result in higher mortality and more fine twig dieback. 10% 5% 0% High Mn Low Defoliation Stress High Defoliation Stress 15% PA/NY NH/VT • But again we see that even without defoliation stress, high Mn results in poorer health in NH/VT. 10% Fine Twig Dieback 5% 0% Low Mn High Mn

22. Sugar Maple Health: Regional Implications 300 600 900 1200 1500 1800 2100 2400 2700 3000 2000 4300 6600 8900 11200 13500 15800 18100 20400 22700 25000 700 ppm 5500 ppm PA/NY PA/NY These data suggest that low Mg and Ca OR high Mn AND excessive stress (≥2 moderate – severe defoliations in 10 years) are required for mortality to occur. In addition poor nutrient status stands that have not been severely stressed are likely to be less healthy and are considered to be at risk. NH/VT NH/VT 3300 Calcium Magnesium

23. Conceptual Model - - - - + Growth and Health • Defoliation • Deep soil freezing • Drought • Air pollution • Root compaction • Armillaria • Reduce chlorophyll • Reduce Photosynthesis • Interfere with carb transport Secondary Stressors + Carbohydrate Supply Acidification + Net Photosynthesis Acid rain also increases Al availability which along with Mn can have a negative impact on available Ca and Mg. + + Available Mn - Available Base Cations Available Al -

24. Summary • Overall, sugar maple health region-wide is good. • However, decline syndrome is a concern range-wide. • Tailoring management to site specific conditions can minimize occurrence of decline.

25. Recommendations Managers can take positive steps to maintain the health of sugar maple by: Choosing appropriate sites for sugar maple culture. Examining nutrition. Monitoring stress events.