Attention, attention you transition zone forestersAre you tired of not finding host and pest descriptions for your shelterbelt and windbreak situations? Then make sure you have the following references in your forest health library: A field guide to Forest Insects and Diseases of the Prairie Provinces by Hiratsuka, Langor and Crane of the Canadian Forest Service ( to order call UBC Press 604-822-5959) and the US Forest Service Rocky Mountain Forest and Range Experiment Station General Technical Report RM-129: Diseases of Trees in the Great Plains by Jerry Riffle and Glenn Peterson. Look on the Forest Service Home Page. Both guides have excellent pictures and disease cycle information.
Back to the basics!! Some references and themes to consider for current
Too much water is a common situation in much of the state, so it wouldn't hurt to review the flooding chapter of Erik Nilsen and David Orcutt's book: Physiology of Plants Under Stress-Abiotic Factors ( John Wiley & Sons, Inc. 1996). While its easy to just say the plants are having a tough time with the water, the environmental attributes of flooded conditions are fairly basic to understand. They reflect the impact of reduced oxygen in the plants daily metabolism and the corresponding shift in the microbial communities that surround and support the root's normal activities of uptake and processing. Key points include the immediate reduction in aerobic respiration in the flooded roots, a shift to anaerobic bacteria, reduced availability of nutrients, and less efficient or terminated mychorrizal support. Photosynthesis and carbon balance are also thrown out of whack. Flooding of roots causes stomatal closure in sensitive plants at the very time large amounts of carbohydrate produced by foliage are needed by the roots due to the inefficiency of anaerobic respiration compared to aerobic respiration. The authors cover the rest of the story in detail.
Now is also the season for seed and cone collection. A good review of the basics in this topic is found in R.E. Farmer's Seed Ecophysiology of Temperate and Boreal Zone Forest Trees (St. Lucie Press-1997 / to order call 561-274-9906). The book has excellent coverage of key concepts: seed development patterns, loading the seed with carbohydrates, fats and proteins; chemical maturation or conditioning, and resulting germinability. He reminds us that parent genetics is a key factor and that cones develop rapidly during late spring and early summer and usually have complete volume by late July, long before maturation or collection. This is the period of predispersal predation characterized by hundreds of diverse insect predators equipped with various devices and strategies for tapping into the seed grocery bag. That is why we ask for so much seed collection and have training for picking up the pest damage. This predator prey system is a complex interaction of crop size, mix of predators, pest life histories and the structure and chemistry of the seed. Even if we do our jobs well and collect sound fruits and process them efficiently, the author reminds us that direct seeding and natural regeneration efforts must also account for reduced germination due to animals, pathogens and aging once the seed is broadcast. He paints a bleak picture of post -dispersal animal predation for all but black spruce (and we would add jack pine).
It seems now-a-days you have little credibility with certain groups in the environmental community unless you use ecological jargon. So I've been updating my word files and would suggest you read Bob Coulson and John Witter's write-up on the effects of phytophagous insects in forest ecosystems in their book Forest Entomology Ecology and Management ( John Wiley & Sons, Inc. 1984). The activities of phytophagous insects such as defoliation, phloem feeding and wood boring are presented as expected occurrences in forest ecosystems that at times have significant impact on the establishment, growth and ultimate values of forest trees. Bark beetles are now gap generators and other old "pests" are now negative feedback regulators of plant community composition and density. The focus is now on the interaction of a rust gall predisposing a tree to ice storm breakage that then fuels bark beetle build up. Product definitions of quality, degrade and volume reduction are not lost, but reworked into the overall role of insects in affecting nutrient dynamics in the ecosystem. Insects are not defined as pests, but as agents that stimulate or reduce plant growth, remove nutrients from plant reserves, change plant structures and modify nutrient cycling. And more.
Confused about what you just read? Better get the books!