Some drawings portray the full graphic horror

The water-colour paints may have run and the bright felt-tip ink faded, but the poignancy of these pictures is not lost on the New Yorkers who still flock to the fire houses, or on the city's firefighters - busy in recent days attending funerals and memorial services for their 343 dead colleagues.

"It's amazing what kids pick up on," says Fire Department of New York lieutenant, Bill Wall. "We were sent a picture which showed one of the twin towers falling down and the other one being hit by a plane."

In the days following the destruction of the World Trade Center, the drawings flooding in to the city's grieving fire department were disturbingly graphic. A number of those sent to Mr Wall's mid-Manhattan station even showed office workers plunging from the burning skyscrapers.

Firefighter Paul Brantmeyer says the 35 or 40 thick envelopes of drawings his station has received from elementary schools across America show the tragedy "has definitely hit home with children".

"Judging by the pictures," he says gazing across a whole wall covered by paintings of the flame-engulfed towers, fire engines and Stars and Stripes flags, "it really looks like their world of peace and calm has been rocked".

Doctor Robin Goodman of the New York University child study center, which is collecting artworks related to the terror attacks, says the act of drawing can be useful for children trying to come to terms with their feelings in the aftermath of 11 September.

Without words

"Kids often communicate through play and drawing. They find it more comfortable since often they do not have the language to articulate their feelings. And, of course, the events at the World Trade Center are particularly hard to put into words."

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Message from a 2nd grade class from Ovilla, Texas

For adult viewers some of the pictures contain eerie anomalies. One young artist has included beside all the death and destruction the figure of a smiling firefighter. Another depicts a burning tower with a grinning fireman flanked by a Dalmatian - the traditional pet of US fire houses.

"Children are not self-conscious when they draw. They may be used to thinking of firefighters as strong and reliable, and the firefighters' attempts to save people at the WTC might have reinforced this idea. It's not surprising they might choose to draw them as strong, reliable-faced people."

Dr Goodman says we should resist the urge to interpret children's drawings, no matter what the content.

"We should never criticise or assume what's going on in a picture. Kids need to get out what they're thinking and feeling in a safe environment. We shouldn't be shocked by the images. Children need to show their artworks and see that their parents are calm about them."

Dr Goodman also warns parents not to use even graphic drawings as a sign that their children may be deeply disturbed by the terror attacks. "In the first month or two, even dramatic pictures are not a problem. The signs to look out for in the months after that are things such as difficulty sleeping or trouble at school."

Fire stations have received hundreds of drawings

While drawing can be a cathartic experience for many children, parents should "encourage" their offspring "but not force them to express their feelings about what's going on," says Dr Goodman.

Camille Tokerud's two sons (aged five and seven) were keen to produce drawings for the fire station near their Manhattan home.

"Neither one has drawn the towers, though many of their classmates have created pictures of the burning buildings. My youngest son now exclusively draws the city skyline. He's seems fascinated by the buildings."

Ms Tokerud's eldest boy has also switched to a single subject matter since 11 September. He now only draws the American flag.

The rain has blurred pictures posted outside

"You see flags everywhere and I heard him telling his brother on the way home from school that putting them out is 'people's way of saying they care and that they believe in America'. I think he wants to be part of that."

With so many adults deeply affected by the horrific events of last month, Ms Tokerud wonders whether children find in drawing a coping mechanism many of their elders lack.

"Perhaps we can really learn something from these kids."