Editing Eastern Prickly Pear (section)

==== Possible Explanations for Absence ====

Given that the presence of ''Opuntia humifusa'' in Beacon Falls between the 1890s and early 1900s is confirmed, there are two distinct possibilities that might explain my inability to locate any of the cacti in modern times.

===== Imprecise Historical Literature =====

For one, the herbarium specimens of ''O. humifusa'' are the primary pieces of evidence confirming their presence in Beacon Falls.  However, neither of these herbarium records actually state that the plants were found on Beacon Hill; they simply relate the collection location as "Beacon Falls".  Hypothetically, this could mean that the herbarium specimens were harvested anywhere within the boundaries of Beacon Falls.

The single piece of historical literature which actually pinpointed the location of ''O. humifusa'' on Beacon Hill was Prichard's book on the history of nearby Waterbury.  While Prichard may have been fairly knowledgeable on the topic of Waterbury, there is no evidence that she possessed the same depth of knowledge concerning neighboring Beacon Falls.  It may well be that when Prichard wrote that "the prickly pear is common on the summit of Beacon Hill, just south of the line of ancient Waterbury", she was simply using Beacon Hill as a general landmark with which most people of that day would be familiar.  It could well have been that the cacti never actually existed on Beacon Hill, but instead existed on some unnamed hill within the same general region.  Prichard would simply have referred to it as "Beacon Hill" for lack of a better-known landmark.  In that case, it is possible that the cacti could instead exist on or around the bald cliffs to the west (on the opposite side of Route 8).  I have yet to investigate this alternate location, but will do so as time permits.

===== Local Extirpation =====

Perhaps a more likely scenario is that ''O. humifusa'' did in fact exist on Beacon Hill between 1890 and 1910, and that it may have continued to flourish for some decades afterwards.  We can assume that Beacon Hill probably would have been sparsely wooded around the turn of the 20th-century, perhaps even largely devoid of trees.  The area of Beacon Hill may well have been cleared to some degree to make room for pasture land and, to a lesser degree, for lumber.  The lack of competition from trees on Beacon Hill would've meant that cacti could take advantage of full sun on the well-drained soil upon the mountain.

However, as the case has been with most old pasture land in Connecticut, the use of Beacon Hill as a grazing area would have expired no later than the very early 1900s, perhaps earlier.  In the time that followed, trees would have been able to begin taking root and growing, eventually culminating in the mature forest and solid woodland canopy that covers the mountain today.  If this scenario is correct, and it seems that it is, this would mean that the cacti documented on Beacon Hill in the 1890s and early 1900s would have ultimately been doomed.  With each passing decade, the tree cover would've expanded and thickened.  In time, any colonies of ''O. humifusa'' living upon the mountain would literally have been shaded out.  Perhaps they could've persisted in the light shade of younger trees for a decade or two, but as the canopy grew more dense, cutting off light to the ground, the cacti would've first lost their ability to flower, and then lost their ability to gather enough sunlight nourish themselves.  At that point, the cacti would've perished fairly quickly, leaving behind no evidence of their presence.

Although this scenario comports quite closely with the known agricultural and ecological history of the Connecticut landscape, what evidence is there that conclusively suggests this pattern of local extirpation actually occurred?

For one thing, aerial photography from the early 1930s reveals that the forest upon Beacon Hill was still somewhat sparse by comparison to the modern forest we see today.  In fact, there were still some cleared parcels of land upon the hill which appear to have been farms of some kind (perhaps tree farms).  Thus, we know that only sparse forest existed on Beacon Hill some 20 to 30 years after ''O. humifusa'' was documented there.  The presence of sparse forest could hypothetically be explained in various ways.  For example, it could have been that the forest was thinned for lumber in the late 1920s.  Perhaps a forest fire tore through the forest in the 1910s, leaving only select fire-hardy trees.  Although these possibilities cannot be ruled out, they aren't especially likely.  In the 1920s, it is more probable that a lumbering venture would've simply clear-cut the entire area rather than merely thinning the forest.  The notion that a forest fire thinned the forest is perhaps plausible, but I cannot find any historical evidence of such an extensive forest fire in that area.  It is most probable that the sparse forest was actually just immature forest; the result of young "pioneer" trees growing upon land that had been entirely clear of significant tree growth at least one or two decades earlier.