On Wednesday, I attended a nature walk/gardening workshop arranged at the Centre By The Sea and presented by biologist Carol Goodwin, an expert in the field of Nova Scotian plants. Her knowledge was impressive, and clever questions from the participants brought her expertise to the fore. Among other things, I listened to how tree populations “talk” – it turns out they signal amongst each other, transferring nutrients across root webs; and how coniferous trees adapt to prevailing winds by shortening their wood fibres, which generates immense elastic tension and hoists the trees upright. Lumberjacks must look out for these tough spots in the wood where the fibers are taught and can withstand the blows of an axe. The most interesting of all was discovering the astonishing biodiversity in even a small area of woodland. White Pine, White Spruce, Black Spruce, Balsam Fir – who knew there are so many types of ‘Christmas tree’!
I’m Portuguese, as well as Canadian, and this nature walk got me thinking about how Portuguese forests are so different from Canadian ones, especially when it comes to biodiversity.
Portugal suffers from a severe wildfire problem. Like California, Portugal has wet, mild winters which favour the growth of dense brush, followed by hot, dry summers at which point the forest floor becomes a matchbox. Portugal is also a more densely populated country than Canada, and so these forest fires risk encroaching upon rural communities, like what happened in Fort McMurray in Northern Alberta in 2016. In 2017, to the north-east of the capital of Lisbon, in a single fire Portugal lost 111,000 acres of forest; hundreds of homes were destroyed, and 66 lives were lost. These fires repeat, year after year. Climate change ranks on the lists of factors, however there is a compelling argument that lack of biodiversity and forest management takes the lion’s share of responsibility. This becomes even clearer to me when I compare what I know and have learned about the Nova Scotian forest to the Portuguese forest.
Devastation follows from the lack of biodiversity. When you take Highway 103 from Halifax towards the Centre By The Sea, the roads are lined with birch, maple, spruce, oak, myriad flora – in fact, the human presence is hardly noticeable – my av (grandfather) visited Canada one summer and described the country as “some houses in the middle of the bush”. Driving to my grandparents’ region of Portugal, the forests along the highway consist only of eucalyptus plantations. Since the 1980s, eucalyptus has been imported from Australia and now dominates the national forest. It is pretty, and it smells nice, but it is also terrifyingly flammable, few birds nest in it, and it outcompetes the native plants. Yet, it is a lucrative tree for the paper and pulp industry. It has the same economic value charred or alive. In Canada, the vast majority of woodland is Crown land; in Portugal, only 3% of forested land is owned by the state. All this means that commercial interests are able to exert far greater control over what is planted, and flammable eucalyptus is the cash crop. And whenever a tract of land burns in a wildfire, before any ecological succession can occur, it is promptly replanted with new eucalyptus! Over decades, this process depletes the soil, making it vulnerable to landslides and wind erosion, which blows from the Sahara.
Human factors relate in a complex way to this ecological wildfire problem. In the 1950s, 80% of Portuguese people lived in the countryside, mostly living off subsistence farming. At this time forests were carefully managed with mostly indigenous trees, and forestry practices were enforced so undergrowth was collected as firewood and forest floors were cleaned. Then, impoverished rural Portugal was drained by waves of emigration to the cities, and abroad. Today, many villages are entirely deserted. The falling population has allowed land to grow fallow, which means more flammable debris. Land ownership is also consolidated by big companies and absentee landlords who plant eucalyptus instead of farmers who use the older, more sustainable methods of forestry. So, the falling human footprint has actually made the land more vulnerable to fires!
Portugal did not always have such a dearth of biodiversity. There once roamed wolves, lynx, boar, deer, and many of these are included in the local folklore; there is even a place near my home called praia da ursa (bear beach), though there have been no bears for centuries. The indigenous forest which once harboured abundant fauna has since been
farmed, developed, and in recent times replaced by monoculture eucalyptus. In contrast to eucalyptus, the indigenous forest is keenly adaptive to drought conditions and resistant to spread of fire. The native sobreiro, or cork oak, has developed evolutionary resistance thanks to its anti-thermal slow-smouldering outer bark layer, which is made out of the same cork we find in wine bottles, amongst many uses.
Largest cork oak specimen in the world located in Portugal. The orange trunk shows where the bark has been stripped.
There are more reasons why cork oak helps to stall fire. Cork oak has a broad, dense canopy which outshades undergrowth. This means less flammable debris.Populations of cork oak trees grow in spaced-out groves. Also, oak leaves, especially the deciduous varieties, decompose faster than eucalyptus leaves and therefore remain for less time on the ground. They tend to decompose in the winter, when debris isn’t a problem since it is too wet for fires. Cork oak acorns are edible to wild boar, among many animals, (and humans) which brings greater biodiversity in turn. The bark also regrows after damage, hence how cork is traditionally harvested as a renewable resource without cutting down any trees.
The region in which temperatures in Portugal are the hottest and driest is south of Lisbon, in the Alentejo. Here, the heat record is 47.4 degrees celsius, and it is common for the dry season to run from May to October. It is also a forested region. Portugal’s exports account for around 70% of world trade in cork, almost all in the dry Alentejo – this is an area far smaller than Nova Scotia, amply forested, not by eucalyptus, but by cork oak. One would expect the hot, dry, forested, southern region to be rife with wildfires, and yet there are virtually none! Instead, the wildfires are concentrated in the wetter and cooler north where eucalyptus is planted. If you look out across land recently ravaged by fire, you’ll occasionally find a lone native cork oak which predates the eucalyptus, and which will grow fresh buds after the rains, the only green amongst acres of black.
Portugal’s wildfires tell a sobering tale of the devastating consequences of monoculture. Native species and biodiversity steward the land and stave off desertification. Subverting usual trends, the declining human presence in the countryside has actually endangered the ecosystem. Ecological commentary often pits humans against nature, suggesting that in order for our environment to thrive, we must give way and let things grow wild. Portugal’s wildfires show the benefits of a carefully managed indigenous forest. This is also a stark reminder to Nova Scotia not to go the way of the monoculture cash crop.