Pine Cone Palooza, Why This Past Fall's Crop Was Over The Top

If you have pine trees in your yard or neighborhood you couldn't miss the masses of mature cones strewn over your lawn, the streets, and on the sidewalks this past fall making a much larger than normal sticky crunchy mess. I know I've been cleaning pine cones up by the bucket full with winter's wind turning the ones remaining in the trees into sap covered projectiles ensuring just as big a cleanup in the spring as we had in the fall. And the bounty was not just ours with off the charts pine cone production reported from eastern white pines in particular throughout the Northeast.

So why were there so many pine cones this past fall? Well, there are a couple of possible explanations which include natural but not well understood cycles as well as weather and climate variables that could have acted as stressors on the trees pushing pine cone production into overdrive.

Natural Cycles

It's well documented that trees which produce seeds for propagation, like pine, oak, maple and the various nut trees among many others, have what's called "mast years" where an unusually high number of fruit is produced by the tree. The term "mast" comes from an Anglo-Saxon word referring to nuts and fruits that had fallen onto the forest floor which then provided food for animal livestock. The term today is used to describe fruits produced by woody plants that provide food for wildlife life squirrels, chipmunks and deer, with "Hard" mast referring to nuts and seeds, and the "Soft" mast describing fruits like berries and apples.

So, based on the widely observed bumper crop of pine cones this past fall, it's clear 2023 was a mast year for the pines made even more apparent by the overabundance of shredded cone debris on driveways, lawns, and decks, courtesy of our furry wildlife friends going to town on harvesting the pine seeds. You may have also noticed that Norway maples appeared to produce an inordinately high number of "Whirlybirds" this past fall as well, which means on top of cleaning up more pine cones in the spring, you'll also have an abundance of tiny maples sprouting in your lawns and gardens to deal with in the coming warm season as well.

It's not well understood why mast years happen with them occurring at irregular intervals from 2-5 years for Oaks, to 4-7 years for maples, and 3-8 years for pines. There are, however, some leading theories which include influences from the weather, the resources that the tree itself has in any given year to use for seed production, to a defense mechanism from insect infestations, to finally predation, which is the killing of one organism for food by another organism, in this case wildlife using the trees seeds as food, which prevents propagation of the tree.

The Leading Mast Year Theories

• The insect infestation defense mechanism theory suggests that if the supply of food, and in the case of the white pine, the food being the pine cone, is inconsistent from year to year, the net result would be to reduce the number of pests that rely on that food source, thus reducing the number of significant infestations that could harm or kill the tree over time.
  
  
• In the case of predation theory, seed eaters like squirrels and other wildlife like turkey and quail, significantly reduce the number of viable seeds by eating them, thus preventing those seeds from germinating and becoming seedlings the following year. According to Perdue University and a study looking at oak trees and acorn production, it's suggested that mast years can successfully overwhelm the seed predators by producing more food than they can eat which would in turn increase the odds enough seed survives to become the next generation of seedlings. In the off years, trees effectively then starve seed predators of their food which lowers their populations and thus makes overwhelming them easier in the boom years. For this to work, however, trees of the same species somehow have to coordinate the effort in a communication process that's not at all understood. But it's believed that chemical signals passed through the air or through underground fungal networks between trees, could be the process or processes that occur resulting in trees across hundreds to even thousands of miles away all working together.
  
  
• The resources theory looks at the amount of energy a tree needs to expend to produce a large number of seeds, which experts agree is substantial. So it would make sense that trees produce large crops of seeds only in years where they have sufficient resources to swing it while having enough energy to maintain the other functions critical to its survival, then take a few years off to recuperate before the process begins again.
  
  
• And finally weather, which is though to play a strong role in both years with an abundance and dearth of seeds as trees all react differently to climate and weather stressors. In the case of white pine trees and pine cone production, cool wet growing seasons favor growth of the tree rather than abundant pine cone production versus hot and dry seasons that can stress a tree causing it to increase cone bud production which leads to higher yields of pine cones the following year.
  

So knowing the theories behind mast years it's natural to wonder what if any role the weather and climate could have played in what anecdotally many of us perceived 2023 as being one of the biggest pine cone drops in at least recent memory. To figure this out we first have to take a look at how pine cones and their seeds develop.

The Path to Pine Cone and Seed Formation

Pine trees are monoecious which means they produce both male and female pine cones. Male cones appear yellowish in color and grow spike-like clusters producing the pollen, then fall off the trees after pollination occurs. They appear in later May and June which corresponds to the time of the year when we notice pollen the most as pine pollen is large and covers everything in a greenish yellow coating. The female cones appear around the same time the male cones do and can remain on a tree for up to 10 years. These are the cones that produce the seeds. Seed cones initially appear in the spring as roughly a half inch long pinkish or green tube with tightly overlapping scales. Over time, the female seed cone grows to a length of 4"-8" and turns brown at maturity.

The two year process begins in the spring of the first year (May and June locally) when male cones appear and produce pollen. This pollen can easily become airborne, moved by the wind up to at least 700 feet from the tree allowing it to make its way to female cones, which can occur on the same or different tree. When this happens the pollen grows into a thin tube at the center of the female cone where an egg is located. When the pollen combines with the egg, fertilization and seed development occurs with the process taking roughly thirteen months by the fall of the second year. When the seed is mature, the female cone opens up and releases it.

So, although seed development within a female pine cone takes quite a long time, the formation of the cone itself happens more quickly with influences from especially the weather and climate during the previous year's growing season impacting the current season's number of cones produced.

So, to gain an understanding of what role weather and climate may have played in the banner pine cone year of 2023 we have to look at conditions during the 2022 growing season, which was unusually hot and dry throughout the Northeast. Widespread drought developed, most severe across New England, with consistently dry to very conditions from May through August. Excessive heat was also in play locally with high temperatures at Albany reaching or exceeding 90 degrees 25 times between May and August with heat punctuated by two significant 6 day heat waves, one in July and the other in August. Summer 2022 averaged 2 degrees hotter than typical at Albany, which is significant, and came in a little over 5.00" drier than normal with drought conditions widespread throughout the Northeast by the end of August.

So, based on what horticultural experts say, it's highly likely that the hot and dry weather conditions in the 2022 growing season stressed the white pines which caused them to increase their cone production in 2023. This could also explain the abundance of Norway maple "Whirlybirds" as well.

Conclusion

Because the total picture behind mast years is fuzzy at best and the highly complex nature of the impact weather and climate has on trees, we can't explain with 100% certainty why there were so many pine cones this past fall. But, based on the fact that it has been some time since we last observed a large amount of pine cones in the fall, it's likely that 2023 was going to be a mast year anyway because we were due, regardless of any impact from weather and climate. But, because so many of us perceived that the number of pine cones raining down on us this past fall was so absurdly high, it's likely 2022's heat and drought triggered a stress crop that only further increased the number of pine cones produced in 2023. So based on the research it's likely we experienced a perfect storm of a natural mast year cycle coinciding with a stress crop brought on by heat and drought in 2022 to result in the super crop of pine cones in 2023.