BREWDOG has “lost the plot”.

That was the assessment by Peta (People for the Treatment of Animals) of the plan by the brewer to cull deer on its estate in order to protect the trees of the Lost Forest project.

Elisa Allen, of the animal charity, even went so far to declare that it “will lose its customers if it thinks that blasting mountain hares and deer with shotguns is going to help restore lost forests, these species’ natural home. All it will mean is the slaughter of many of the beloved animals who live there.”

It’s an emotive intervention in an already tense debate, in which there is significant backing for the idea that culling deer does give breathing space for forests to restore, not least of which the 2020 Scottish Deer Working Group Report.

While there are studies that question the effectiveness of deer hunting and culling, including one 2012 European Commission report which advised that hunting did not work, and that forests would be better protected through “close-to-nature” management techniques, most of the modelling and research suggests that at least some culling is needed. The regrowth of forest at the National Trust’s Mar Lodge and Glen Feshie also suggests their zero-tolerance approach to deer is working.

READ MORE: Rewild Scotland: "Beavers in all rivers. Lynx and wolf back.”

In other words, Brewdog has far from lost the plot on its way to the Lost Forest, with its plans for fencing off areas and driving off deer or, as a last resort, shooting them.

Allen nevertheless was fierce in her attack, saying: “If the company wishes to retain any of its ‘planet-friendly’ credentials, it must remember that the planet is home to more than just humans and switch to one of the humane, sustainable methods of population control that exist – or risk losing all credibility.”

I agree that we should strive to follow the most humane route in all things but this attack on Brewdog’s plan is a reminder of the difficult territory we are entering as we attempt to tackle the climate and biodiversity crises. We do not yet have a route map in terms of ethics. We are hampered by confused attitudes towards animals, nature, and all living things.

Scientific research in recent years has shown us the importance of trees. Yet, we humans are still particularly poor at protecting and defending plants, except when they are useful to us. The philosopher Peter Singer has described the tendency to privilege the immediate survival and health of our own species, as speciesism. Peta’s website carries a definition of this tendency, as “a prejudice or attitude of bias in favour of the interests of members of one’s own species.” It adds that, “it’s also speciesist to treat one animal’s life as more valuable than another’s.”

It seems to me there’s a whole other level of bias when it comes to looking at the issue of the health of our environment and the wider biosphere, and that’s what I might call kingdomism – the privileging of the protection of the animal kingdom over that of the plant kingdom. For this reason, David Attenborough’s The Green Planet, by helping us understand the complexity of plant life and our interdependence on it, is probably his most important yet.

We humans also have a bias towards protecting fluffy, charismatic animals. If something is particularly cute, it’s more likely to garner an army of defenders, which is what happened when the wallabies of Inchconnachan island were slated for eradication or removal as part of plans by Kirsty Young to reduce the island’s non-native species to zero.

A petition to save the wallabies has already nearly 35,000 signatures. An intervention by Chris Packham, who has interestingly previously spoken in support of deer culling, has diverted their fate. “I applaud,” he said, “efforts to re-wild but you can’t blame the wallabies. The way to do it is to catch the wallabies and move them elsewhere. I don’t think there would be any problem finding them a new home.”

How can we be humane, while also reversing a long history of human impact? One of Elisa Allen’s suggestions is that Brewdog seeks more humane ways of killing the deer. Key among these is dart-delivered birth control for deer. This is a decent suggestion. But reports tend not to recommend it. A review article by Peter Green for the Deer Initiative found: “Contraception will not reduce numbers in the absence of other means of removal until older females die naturally, which may take many years.”

The processes of rewilding are forcing us to look again at what matters and to evolve a new ethics that encompasses a genuine respect for all life. Who and what, in this new landscape, do we fight for? And what about humans, too? My concern about Brewdog isn’t just about what it does with deer. It’s that they will turn out to be Green Lairds who get rid of humans too.