Reply To: Pacific Northwest Truffles

Alana McGee

Actually by you- it’s more like late Fall through spring- provided you have moisture. That’s the caveat in California, you have to have rain/ or at least coastal moisture!

Elevation does play a role in fruiting. It is not well understood as there is not enough scientifically collected data- but from observational experience, yes. Stuff at Higher Elevation starts fruiting earlier.

As for temperature causing fruiting/ripeness: Wow- a big topic- it will depend on species. Studies have not been done (scientifically, to our knowledge) for native species in this regard. They have been done however on this for Perigord truffles (Tuber melanosporum), basically in the last year- so it’s a pretty new understanding. The oversimplified answer is for T. melanosporum fruit bodies to mature (aka become ripe) they need a temp spike downwards. Not freezing. It is more complex than that, and I won’t pretend to understand or know all about it, but that is the simple answer.

*Those of you who have orchards who are reading this (you know who you are!)- ask your consultant for specifics if curious because I am paraphrasing and condensing a lot. It may be different for T. aestivum/uncinatum and likely is for T. borchii as we know both those species have a much broader natural range. There is data out there for daylight hours fruiting temps etc for those species. There is not for natives.

In general truffles need moisture to fruit/ ripen. Our understanding of how they go about this is changing yearly. Again, this is varies from species to species. There is a lot we don’t know. We used to think they would take 6 months to grow (primordia to sporocrap to fruit body to ripening), now it is more likely they are more closely related to what mushrooms do with ‘fruitings’ and flushes.

It gets pretty technical if I start getting more in detail.

That being said, truffles will not all be ripe at the same time. They will ripen continually throughout the season. Oregon winter whites (oregon white truffle species in general) have a shorter season than blacks. In an Oregon white patch (for example) bunches of them can be growing, but only a few ripen at a time and then a week later more are ripe, then a week later nothing and then 2 weeks later, lots. We don?t know what environmental factors contribute for sure to the ripening.

Tidbit of data: North of Eureka on the coast in March of last year Oregon white truffles were fruiting. We found a couple in the Santa Cruz Mts in January- but it was SO dry.

Observationally we have noticed a different pattern with Oregon Blacks (Leucangium carthusianum) * also found in Europe and classified as Picoa* and we feel like ripening and fruiting & growth is related to rain events several weeks prior- but this is observational. To my knowledge there is not published data anywhere on it.
I’m curious, because if you miss that prime 1 or 2 week period, you can miss the entire season.
This isn’t a problem with truffles. Yes you can miss big ripening events, yes, but if you have a productive spot, it will produce continually in varying amounts over the course of the season aka months.

For Wa & Or (BC tends to fruit a little sooner we think, CA later? but again, limited data) Oregon winter whites (T. oregonense complex*) are generally best in Dec/ Jan/ Feb (but we will find them Nov thru March- again depends on local weather patterns)

*some of the complex can be found slightly earlier

Oregon Spring whites (T. gibbosum) they call the ?june? truffle. We found them in January last year (they fruit when they fruit!), but very few people have large patches of Oregon Spring whites. I know two people in oregon who may have the only claim/ knowledge on commercially productive T. gibbosum sites and they tend to fruit in late april/ may/june. My knowledge on those is more limited. We find a few here and there mixed in in one of our productive black sites, but we don?t find a ton. Most would likely confuse them for Winter whites as well but there are subtle differences. Again, it is actually considered a complex species (as in there are genetically many, not complex as in confusing)

Blacks tend to have a longer season. We have student who found them in July. We are finding one or two now, but not many. Again, Nov- April really, but best late Dec to April/May even! One year was I finding a decent amount by beginning of Nov, but again it totally depends on rainfall, and temperatures.