I found a notice in our mailbox this afternoon. The council wants to take down the big oak tree next to the footpath. Hmm. It will be a shame to lose it but I suppose it will save me having to rake up its leaves in autumn. I’ll miss the shade and the birds. Oh well.
Me: “Hey Marg, the council wants to take down the big tree in front.”
Marg, shouting from the other room: “Why do they want to do that?”
Me: “The notice doesn’t say. I suppose it will save them having to clean up leaves on the street. Or, maybe it’s buckling the concrete footpath too much. Or maybe it’s interfering with power lines. They must have their reasons.”
Marg: “Well, those reasons better be pretty good! We are losing too many big trees in this town. It is beginning to look like a concrete jungle. And, we need more trees!
Me: “What’s the big deal? There are plenty of trees around here.”
Marg comes into the kitchen and sits at the table. She looks cross. “Darling…” She looks up at me from the table with that exasperated looks she sometimes gets. “In the times ahead, we are going to need those trees”, she says patiently. “People don’t realise how important trees are. Our changing climate means summers are going to get hotter here in Blenheim. Trees make places cooler by transpiring moisture to the air on hot days.”
Marg: “Transpiration, it’s like evaporation from the leaves. With all the asphalt and concrete in this town, we’ve created a whopping big heat-island in Blenheim. It is well known that cities get hotter than countryside in the summer months. That’s because asphalt and other dark surfaces absorb heat from the sun while plants counter that heat by transpiration, making things cooler.”
Google Assistant chimes in: “Trees provide other important environmental services. For one, they catch rainfall in their leaves and branches, which reduces storm water runoff and slows down floods. Their roots also provide channels into the ground where rain water can percolate down into the groundwater, further reducing storm water runoff.”
Marg: “Thank you, Google. You know, Tom, NIWA’s climate change predictions for Marlborough suggest more intense rainfall events in the future, so we can expect more flooding. More trees will help reduce flooding as well as keep things cooler.”
Google: “I wasn’t finished! They also provide habitat for wildlife, muffle road noise and absorb carbon dioxide from the atmosphere, helping to reduce greenhouse gas…”
Me: “So, how much CO2 does a tree like that big oak absorb, anyway?”
Google: “According to the US EPA, a sixty year old scarlet oak captures about 250 kg CO2 per year. In three years, one of these trees will offset the emissions from your holiday to Fiji next month.”
Me: “That’s impressive. Maybe we should plant a few more…”
Google: “I’m not finished about trees yet! They also slow down surface winds, preventing wind damage to homes and businesses.”
Me: “But, wait a minute. Don’t they sometimes fall in wind storms, wrecking houses and killing people?”
Google: “Trees aren’t maintenance free, Tom. They need to be cared for and pruned every once in a while to keep them healthy and strong.”
Me: “Marg, maybe we can talk the council into keeping the old oak, after all. I’ll call the council tomorrow morning and talk to them about it.”
Marg: “I love it when you take charge, darling. If you can save the tree, I’ll buy you leaf blower for Christmas. An electric leaf blower.”
The Blog posts are a collection of opinion articles written by CKM member Tom Powell for the Marlborough Express. Tom is a retired geologist who came to New Zealand in 2004 to work in the geothermal industry on the North Island, is a New Zealand citizen and now lives in Blenheim.