Quick Answer: Few studies have been done on the subject, but so far they have shown little to no effect on picking vs cutting on future mushroom productivity. Likely, every mushroom reacts differently to these forms of disturbances, thus I recommend pickers use their best judgment.

If you’ve been foraging for wild mushrooms, or just done reading on the subject, you’ve probably heard someone say “It’s better to cut than it is to pluck”. This belief holds that cutting wild mushrooms from their stems when out in the field is better for the fungus than picking them directly. 

While this has great intentions, the truth is we don’t know what’s better. There is also controversy on the subject, with many well-experienced mycologists suggesting picking is better. The main argument pro-picking is that leaving residual stem butts in the field can promote disease-causing organisms which may interfere with future productivity. We will dissect this later. 

What Does The Science Say?

Up to this moment, there have only been two studies on the subject, which are regularly cited. These are below.

• Egli, Simon, et al. “Mushroom picking does not impair future harvests–results of a long-term study in Switzerland.” Biological conservation 129.2 (2006): 271-276.
  
  This study by Egli and colleagues found that the systematic harvesting of forest fungi using either picking or cutting techniques did not adversely affect the production of fruit bodies over the 29-year study period. The data showed no significant difference in the abundance of fruit bodies or species richness between harvested and non-harvested sites, indicating that both picking and cutting methods were sustainable in terms of fungal yields. On the other hand, the study did show that trampling could negatively affect production.
  
• Norvell, L. L., and Judy Roger. “The Oregon Cantharellus study project: Pacific golden chanterelle preliminary observations and productivity data (1986–1997).” Inoculum 49.2 (1998): 40.
  
  The Oregon Cantharellus Study Project was initiated by the Oregon Mycological Society and largely run by volunteer efforts. It was published in a technical document, but it is not a published scientific paper. In their study, they recorded the productivity of Chanterelles from 10 different forest plots. They showed no significant difference in plucking-vs-cutting, although removal of the fruiting body was shown to have a slight increase in production. 

My Thoughts On The Science

Realistically, the science on this subject is pretty limited, and I don’t think we can conclusively say whether one harvesting technique is better than the other. The studies done so far support the idea that long-term impacts are probably negligible compared to other forms of disturbance. 

My personal opinion on the subject is that every mushroom may interact differently with each method. If you’ve picked a fair share of mushrooms, you probably know there are species with a tendency to break when picked. Amanitas are like this for example, as the bulbous volva needs to be pulled out with care. Other species, like Chanterelles, love to come out with the entire stem-butt. Perhaps these are distinct adaptations. 

So What’s Better, Picking Or Cutting?

If I’m going to be honest, in most cases, I’m a picker. I like to pull the entire mushroom from the ground, base and all. After picking, I clean the stem butt off with a knife, leaving as much of the flesh as possible. Afterward, I place it in my basket or bag. The biggest reason for this is to make sure I get the most of the mushroom stems in my harvest. If you were to simply cut in the field, you could often miss out on a good chunk of the base.

Sometimes if I’m harvesting small mushrooms that are more tedious to pick (Laccaria, Craterellus, Marasmius) then I do cut them. This saves me time and makes sure the mushrooms go into my bag free of dirt, leaf litter, and other debris. 

If you asked my opinion, I’d have to say that it makes sense that picking would be better than cutting. Leaving a stem butt to rot could very likely feed potentially pathogenic organisms. It’s likely mushrooms are already adapted to this since they rot in the field all the time, but perhaps removing them could benefit them. One final thought is that mushroom growers always pick and never cut, and there’s a good reason for it.