Terraces, terraces everywhere on these vertiginous slopes. (And believe me for yours truly they are sickeningly vertiginous.) Sick, but impressive, as lines of terracing snake along the contours around the hills that drop away into the azure sea. The terraces allow crops of grapevines, vegetables, olive and fruit trees to be grown on slopes that would otherwise be far too steep for cultivation.
Ancient stone terracing along the Cinque Terra
The stone walls that comprise the terraces date back to the BC when Roman soldiers were rewarded with land to farm as a pension for their service to the conquering generals who happened to make Rome great as a spin off to furthering their own political careers. Just why the soldiers would go to the trouble of covering these massive hills with stone walls when there was equally good agricultural land waiting to be conquered and cultivated on not so disrant flatlands remains a mystery to me. But build the walls they did, and generations of peasants have been adding to the walls for over two thousand years since.
Stone path through the olive trees
Clambering up and down these steep hills overlooking the Mediterranean, I feel so inspired by what has been achieved here. These stone retaining walls sit on slopes as steep as the Bronte Gully where I have been labouring for two decades turning tip into rainforest. Our plan is to establish a bit of wild nature on what was a rubbish dump. While much of Sydney has retained a high proportion of bush the area where I live has been relentlessly urbanised and bush accounts for a tiny fraction of 1% of land area. We need to manage our cityscapes far better if we are to live in them sustainably. Our cities can no longer afford to follow the Roman city model of relentless bricks and mortar relieved only by grand monuments to the alpha-male ego. We need to bring wild nature back into the city, and the best way to do this is to lend nature a hand by cultivating a natural ecosystem until it becomes self-sustaining.
Young rainforest canopy of the revegetation project in the gully.
The height of those slopes at home may be minuscule compared with these Italian hills, but the steepness of the terrain is the same, and the challenge of cultivation is the same – how to stabilise the ground, prop it up against the force of gravity so that plants can grow. Here, the crops are grapevines, olives and vegetables for human consumption. At home the plants are rainforest trees that will one day take over the role of stabilising the slope themselves.
View south east down Bronte Gully. In left foreground is recently terraced and planted ground. Beyond this 7 year old planted regrowth. Running diagonally from lower right is 15 year old rainforest with coral trees (exotic weeds) with red flowers and no leaves. These coral trees covered most of the steep slop when our revegetation program began.
While in Cinque Terra, the stones are indigenous, collected from the fields, at home they are dumped building rubble from the demolition of local terraces in the 1970s.
Looking down a recently terraced slope of over 60 degrees. Note the amount of building rubble
But until the roots get a good hold on the steep slopes, the young plants are susceptible to gravity’s relentless pull. Each time we come through clearing the weeds competing with the young trees for water, nutrients and space, our every step creates a little avalanche pushing soil and rubble down hill. Terracing is essential if the rainforest is to flourish.
Looking up the slope
Furthermore when it rains heavily, as it is want to do in Sydney, the damage is much worse, precious soil washed away. Our local council decided to carry out a bit of their own landscaping last year, effectively turning a large area of paving and grassed parkland into catchment draining into our land rehabilitation site. No sooner had they finished this than a heavy downpour cut a canyon through our most recently rehabilitated slope, washing out new plants and dumping half a ton of soil and mulch at the bottom of the slope. In amongst that lot was a mass of weed seed deposited into an area of established rainforest that had been free of weeds for eight years. Thanks guys!
Erosion gully created by surface runoff on steep ground at Bronte after heavy rain washed out mulch and soil. Note wooden terracing remains intact. Otherwise damage would have been much worse.
The sandy soil here is precious because there is so little of it. Mostly the ground is building rubble: bricks, chunks of concrete and sandstone from houses demolished to make way for a shopping mall 40 years ago, in the good old days when a developer could just dump his rubbish in the nearest convenient bit of bush. Our site is effectively a landslide of building rubble covered in weeds.
Gully gouged out of hill by surface runoff. This ground was previously covered by 30cm of mulch. Note the building rubble exposed by washout.
The only effective way to prevent the further land sliding down this slippery slope, as the Roman legionnaires realised is to terrace, little walls damming the downward flow – lots of them all the way up the slope.
Looking across the slope to the weed-fields of lantana, cestrum, Madeira vine beyond. These dense weeds must be removed before terracing, planting and mulching can be done.
This way, soil, mulch and water accumulate in the pockets behind the walls, and we gardeners can tend the plants on level ground without adding to the problem, and heavy rain soaks into the ground instead of flowing downhill washing all before it.
What I find so inspirational here in Cinque Terra is the rock walls. Just as at our site at Bronte, the ground is mostly rock (well brick, concrete and rock at Bronte). We have been using treated pine poles to build our little terraces. But these are costly, and we have very limited financial resources. However, if I can use the abundance of bricks and stone in the ground to build dry-stone walls, we not only get our retaining walls for nothing, but we also clear the ground of the excess of brick and stone. I have done this in a few places in the past, but have been put off because it is so time consuming. I guess I just need to change perspective. These walls and the resulting rainforest are going to be here for a long, long time.
Dry stone wall in the gully