BERKELEY -- Over 300 volunteers will fan out across Alameda County Wednesday morning to count the homeless in a 24-hour blitz at 33 sites that will determine whether a downward trend continues or if the recession has caught up to those most vulnerable.

The number of homeless in the county fell 13.6 percent from 2007 to 2011, said Elaine deColigny, executive director of Hayward-based Everyone Home, which makes the count every two years. The 2011 count was 4,178, but the study did not break down numbers by region.

DeColigny said a change in strategy to getting homeless into housing where they can work on issues like drug addiction and their mental health, rather than requiring them to get sane and sober as a prerequisite to housing is part of the reason the numbers have come down over the years.

"What we know is people get better in housing and are more able to follow a wellness plan," deColigny said.

On the other hand, numbers could be up this year because homelessness tends to be a "lagging indicator" of economic conditions, and this year's count could be a reflection of four years of recession.

"While the economy has turned around for the middle class and the corporate class, poor people have continued to tumble downward," deColigny said. "It will be interesting to see how many first-time homeless we end up with."

JC Orton, who has managed the Berkeley Emergency Storm Shelter for a decade and who will be counting the homeless Wednesday, said he's noticed more homeless youth. The good news, he said, is homeless veterans are getting more help.

"We're seeing many more young people under 25 who usually would leave during the winter months when it gets cold and rainy," Orton said.

Berkeley shelters have become more accommodating to younger homeless and they are more likely to seek shelter in the same places as older, more chronic homeless, he said.

"The other thing is veterans are getting a lot more response," Orton said. "For one reason or another the federal government created more funding for veterans. The men's shelter on Center Street in Berkeley now has a separate section just for vets and they are given flexible hours."

In 2009, the last time Everyone Home broke out homeless numbers by region, Oakland had 2,091 homeless while Berkeley had 680 out of the 4,341 in the county.

Everyone Home has a budget between $400,000 and $500,000 a year and has three employees, deColigny said. The nonprofit counts the homeless for local government as a requirement to receive about $25 million a year in federal funds for homeless programs.

This year's count will start at 7 a.m. Wednesday and volunteers will visit 33 randomly selected sites including shelters and meal sites where they will interview 2,000 individuals, she said. Volunteers do not seek out individuals living on the streets, so the count is more of a scientific estimate than an attempt to count all homeless.

Doug Oakley covers Berkeley. Contact him at 510-843-1408. Follow him at Twitter.com/douglasoakley.