Morel harvesting season typically begins in mid- to late spring, and lasts less than three weeks. Within a very modest range of latitude or even elevation, that morel fruiting season may vary by as much as two weeks, while producing abundantly in one area and, a few miles away, barely producing at all.
Morels are extremely sensitive to environmental conditions. Demanding specific soil moisture and relative humidity, needing exact sunlight levels simultaneously with exact air and soil temperature, and relying on prior year's conditions to help the fungus establish its root-like network means that morels will only produce if all conditions are met at precisely the right time in its lifespan.
Morels sprout and mature in a very brief span of time - mere days in most cases. It is this unusual growth spurt that contributes to the myth that morels mature overnight (even instantly). A friend's sister, when they were young, used to tantalize him during picking time by having him close his eyes, turn around, and then open his eyes to see a mature morel where he was certain none had been moments earlier. He was well into his teens before she admitted to trickery by spotting the morel before she spun him around!
Unfortunately, morels also pass maturity and collapse into pulpy masses in mere days, as well, making the harvest a rush against time.
Equally perplexing and frustrating is the morel's method of propagation. Although morels rely on spores contained within the fruit to reseed, the real method of producing fruit each spring is the network of spider web-like filaments that it develops less than a couple of inches beneath the soil. Imagine a carpet of veins and capillaries running through the leafy compost of a woodland floor, and you will have an approximate picture of the dozens of yards of fibres that spread morels across a given growth area.
This network does not start to grow in the fruiting season. Rather, it starts the summer before, after the dying morels release their airborne spores. These spores progress through three key phases of development and growth, until the web of connecting root fibres have infiltrated the soil substrate. In early spring, these new networks will then produce lumpy nodes just beneath the surface that, when conditions are optimal, will develop into morel fruits.
But the process does not stop there. That delicate network will remain intact underground, surviving some of the harshest winters in North America. While parts of the fibrous web may be broken or disturbed, the remainder will survive, providing a nutritional link for next season's morel crop.
This habit means that, even when there is no fruit production one season, or when extensive harvesting seems to strip all spore-producing morels from an area, the next season, if conditions are optimal, an abundant crop may occur, yet disappear within days if harvesters miss the key window of picking opportunity.