Wild plants in Berlin after 1945

Without a countryside to go to the plant watchers of West Berlin looked within the city and urban ecology was born out of the surprise of what they found. So the story goes. A very nice article is 'Flora and Vegetation Reflecting the Urban History of Berlin' by Herbert Sukopp (2003). The effects of the Blitz on the wild plants of England and especially London has been covered here, here and for WW1 France here. Sukopp writes about Berlin in '45.

In a historical context, sites bombed during World War II have played an important part in the development of the urban flora and its investigation. Only few years after the bombing various plants had colonised the ruined houses. In many cities the war damage and its effects gave rise to special studies of the rubble flora and fauna (Düll and Werner 1955/56, Scholz 1960 and others). During the colonisation of rubble, which offers warmer and drier conditions than natural habitats, plants and animals from warmer regions of the world found suitable conditions. Many plants that had been rather rare have become permanent membersof the urban flora in war-damaged Berlin.

After World War II an intensive and spontaneus development of vegetation began on the rubble, proceeding in more or less rapid succession from short-lived and perennial stages of herbaceous vegetation to shrub and forest-like stands. The variety of species on such inner-city waste land is surprisingly large. Thus a site at Lützowplatz in Berlin-Tiergarten accommodated 140 species of seed plants and at least 200 taxa of insects (Weigmann et al. 1978).

Dispersal of organisms and development of vegetation can be studied on rubble sites on a large scale and in an environment that differs considerably from previously known ruderal places. As Pfeiffer (1957) wrote: “The recolonization of rubble, created in many cities due to the activity of bombers in the last war, has unintentionally become a tremendous natural experiment, which with respect to its size, must be compared to the colonisationof new habitats created by volcanic activity”

Globalization creates forests [in some places]

Quoting from an interview between the Yale environmental website e360 and Susanna Hecht on the positive effect globalization has on the regrowth of forests in El Salvador:

With globalization and structural adjustment programs, things like corn and other basic staples were coming in at import prices that were below the cost of their production in El Salvador. That meant if you were going to sell your corn, you would be selling it at a loss. So peasant agriculture soon collapsed, allowing reforestation.

Another thing about globalization is that for niche commodities it’s quite good. Those are crops that get a premium. What it meant in the case of El Salvador is that things like cashews and coffee and artisanal products made from wood had a vigorous market compared to the crummy returns you got for corn and the milpa crops [Subsistence crops such as beans and squash.] There was a shift to higher value crops, many of them arboreal.

More than half the households receive remittances from various countries, mostly from family members in the Los Angeles area. People work at jobs here in the U.S. and send money back. If you are getting remittances, you live a lot better — it basically doubles your income. Instead of having to produce corn with low yields on, say, steep slopes, you could buy the corn for the tortillas and not have to go into these forest areas. The result was a lot of land abandonment. The land was allowed to go into successional activities or forest-based economies rather than being used for producing basically corn.

The global market is against agriculture and the farmers themselves receive so much money from relatives abroad that they can retire from farming anyway! This is happening in Europe as well as noted earlier. But a secondary forest is not the same as a primal forest and lots of people are worried that Hecht's work in the wrong hands can give a rational for the deforestation of old growth forests. Earlier we quoted David Quammen warning that the invasion of weedy species and the decline of local biodiversity creates unwanted international uniformity. Hecht responds to this in a way that with a bit of effort could still be interpreted as dismissing concerns over deforestation be positively addressing the biodiversity of second growth forests. I wonder if the second growth forests of El Salvador can be understood as novel ecosystems. 

I am always surprised how controversial this is. I think it’s partly because some conservationists don’t count secondary forest as real forest. They see forests as ahistorical and apolitical, and the forests just aren’t. It was pounded into people in Bio 101 that human interaction with forests is destructive. But there has been extensive human influence even in places like the Amazon. What my work there taught me is that these places weren’t empty, and that if you only look at the ecological side, you don’t see the social side of forests. The conservationists really don’t like this.

What helped me to see forests in degraded areas was being around people messing in the forest. So I was primed to see the El Salvador forests and not to disparage them. To me there is almost no primary forest; it’s all secondary forests. All landscapes will have to be working landscapes. If we have lots of people with forests, we should be thrilled. And we should be really thrilled when the forest comes back because we have a narrative that it doesn’t come back.

There has been a recognition that inhabited environments can have major conservation value. Even though the reforested areas are fragmented, they are quite diverse in terms of landscape. They end up actually having a rather interesting impact at regional levels — they scale up rather better than one might imagine. Even those hedgerows can provide something like 40 to 50 percent of the biodiversity that you get in a riparian system in El Salvador. And hedgerows, land demarcations, woodlots, gardens and domestic forests of various kinds all end up supporting biodiversity in ways that are kind of surprising. For instance, the bird diversity of El Salvador is about equal to that of Belize, which has a fraction of the population and far less fragmented forests.

The image comes from Hecht's paper 'Globalization and Forest Resurgence: Changes in Forest Cover in El Salvador'

Activities of the wild urban euro-woodlands

The Don of the fabulous Green Hermeticism blog pointed me to research on 'Wild urban woodlands' ages ago but only now have I managed to have a proper look. I think most of it deals with the controlled reforesting of abandoned landscapes (empty cities, decommissioned coal mines, etc). In a section on 'industrial fallow lands' as pedagogic challenges (the cryptoforest as a free school?) the following table is given. 

Dog walkers as an unrecognized class of urban explorers? 100 Lingerers? 152 Acts of adolescent activity (sex?)?? 33 Foraging acts (berries plus mushrooms)??? Seven arsonists???? One hunter, hunting for what????? & who can tell what somebody is up to?   

The afforestation of the Arctic

Global warming is melting the ice and creating space for weeds. All this is disheartening but I will be interested to learn how the primary people of the North will learn to exploit these new biological niches. The images show the Normalized Difference Vegetation Index of the globe and the arctic.