Posted a similar thread last year, never found the precise cause of green cones falling from one specific D Fir tree (out of about 200 near the house)
Just this morning about 6:30 AM, DW went out to get the paper, no cones on the ground. On the way in DW heard a couple fall and hit by one. Within 5 minutes, must be 100 green cones on the driveway, one falling about every 1 to 5 seconds!
Noticed that the sun has just hit the top of the tree, a D Fir approx. 105 years old. NO wind this AM, not even a breeze, dead still. Watched as cone fall starts moved down the tree in sync with the line of sunlight!
Grabbed the binoculars and sat outside and watched them fall. No squirrels or birds in the tree. Over the last 45 years here, have never seen this particular tree drop cones like this.
Did see a couple specific cones let go, both were from huge clumps of cones (the cones all touching each other). One other area where I saw specific falls originate was where the branch from another tree touched. What all seemed to have in common was the line of sunlight first hitting the area of the cone clumps.
It is now 7 AM here, looked again and the tree that was dropping cones is now in the shade of the upper crown of a 160 ft Fir to the East. Just like flipping a switch , the green cones STOPPED falling when the shade hit the cone area of the tree that was dropping cones.
Hypothesis: Sunlight heat dense clumps of green cones, heats slightly, cones push each other off. Sunlight shaded, cones stop dropping. Probably the tree last year once all cones were equally warm the dropping stopped.
Why now, after 40+ years and not dropping green cones? Possibly, IIRC, related to lower rainfall 2 years ago followed by good rains the last 2 years. Recall that 1987 was a VERY dry year followed by wet years yet did not notice green cones falling then (may have just been busier?)
Just this morning about 6:30 AM, DW went out to get the paper, no cones on the ground. On the way in DW heard a couple fall and hit by one. Within 5 minutes, must be 100 green cones on the driveway, one falling about every 1 to 5 seconds!
Noticed that the sun has just hit the top of the tree, a D Fir approx. 105 years old. NO wind this AM, not even a breeze, dead still. Watched as cone fall starts moved down the tree in sync with the line of sunlight!
Grabbed the binoculars and sat outside and watched them fall. No squirrels or birds in the tree. Over the last 45 years here, have never seen this particular tree drop cones like this.
Did see a couple specific cones let go, both were from huge clumps of cones (the cones all touching each other). One other area where I saw specific falls originate was where the branch from another tree touched. What all seemed to have in common was the line of sunlight first hitting the area of the cone clumps.
It is now 7 AM here, looked again and the tree that was dropping cones is now in the shade of the upper crown of a 160 ft Fir to the East. Just like flipping a switch , the green cones STOPPED falling when the shade hit the cone area of the tree that was dropping cones.
Hypothesis: Sunlight heat dense clumps of green cones, heats slightly, cones push each other off. Sunlight shaded, cones stop dropping. Probably the tree last year once all cones were equally warm the dropping stopped.
Why now, after 40+ years and not dropping green cones? Possibly, IIRC, related to lower rainfall 2 years ago followed by good rains the last 2 years. Recall that 1987 was a VERY dry year followed by wet years yet did not notice green cones falling then (may have just been busier?)
