Two families are still unable to go home, and other families are unable to get out of their homes, after floodwaters swollen with forestry logs closed 17 bridges on the East Coast.

Environmentalists are calling for an end to "Wild West" clearfelling of forests on steep land after logs washed into rivers and exacerbated the flooding at Tolaga Bay at the weekend.

Tolaga Bay Area School acting principal Julie McLaughlan said two teachers and 10 students were likely to be out of school for several weeks after the weight of logs shifted the Wigan Bridge on Tauwhareparae Rd about 30cm, forcing the bridge to close.

"Most of the roads will reopen tomorrow. Just one of the roads is going to be shut, they think for about two weeks," she said.

"We have two teachers and 10 students affected. Most of the teachers have email addresses for the families, so we can email them their work."

Wigan Bridge on Tauwhareparae Road near Tolaga Bay is covered in logs washed downstream in the weekend downpour. Photo / Supplied

Civil defence coordinator Pop Milner said two families in the Mangatokerau valley, including one that was airlifted off the roof of their home on Monday, were still unable to return to their homes.

Dramatic pictures issued by the Gisborne District Council showed a huge build-up of logs at many of the 17 bridges in the area that have been closed.

Milner said some were willows and poplars, but most were "slash" - smaller branches left on forestry sites after the main tree trunks have been harvested,

"The bigger logs are from the forestry because you can see the chainsaw cuts, those are the ones that have jammed up on those bridges," he said.

Ruatoria environmental consultant Tina Ngata said the forestry industry was "absolutely" to blame for the flood which forced the Mangatokerau family to evacuate their home.

"The forestry industry on the East Coast is known as the Wild West of forestry," she said.

"Our waterways have already paid the price, and we have paid the price with the lives of young men [forestry workers] from our families, and we are seeing this poor family paying the price and being absolutely traumatised because of the greed and the prioritisation of profit over the wellbeing of our land and now our wellbeing, our safety."

Gisborne resource management consultant Murray Palmer said clearfelling forestry should not be allowed on the steepest land.

"We have to look at it here because we are suffering more severe events regularly, and we do have the second-largest plantation forest area in the country," he said.

"I would be really keen to work with the Gisborne District Council about how we can use Resource Management Act processes. I think that is making plantation forestry a discretionary activity on lands that are steep and vulnerable or where there are sensitive populations downstream."

A family had to be rescued from the roof of their home on Monday after logs and floodwaters surrounded them. (Photo / Supplied)

Long-serving former Gisborne District Conservator Trevor Freeman, who retired 18 months ago, said he was horrified by Forestry Minister Shane Jones's plan to plant 1 billion trees because of the risk of expanding plantation forestry on vulnerable land.

"There doesn't seem to be a lot of thought about where they are going to be planted," he said.

"Are we just going to be repeating the problems of the past by replanting some of the steepest land?"

However, Gisborne Mayor Meng Foon said the council had already imposed new conditions on resource consents for forest harvesting, requiring companies not to replant close to waterways, allowing native forest to grow up again to stop logs being washed away.

"That is going to take many years to implement," he said.

"A lot of them are planting permanent forests like mānuka so they can benefit from the mānuka honey."

He said two new mills had also opened in the district recently to process "slash", encouraging forestry companies not to leave it lying on the hills.