Declan's funeral will be held at Elim Church on Thursday.
Maungatapere School, which Declan attended several years ago, posted on their Facebook page that the proceeds from a movie night fundraiser being held tonight would go to the Halford family.
A family friend of the Halfords said his parents, Luke and wife Deborah, were heartbroken.
She described Deborah in particular as "absolutely devastated".
"He was one of six children, she's got five more and she's got another baby on the way so it's pretty tough."
She said the accident seemed to be the result of a misstep, and Declan was normally a good tree climber.
"He was just out doing what boys do. We're both quite outdoorsy people and we encourage our children to be outdoors taking risks.
"He was a very confident climber and he was usually outdoors doing something. It was just a horrible accident."
The family had "amazing support" from the community, she added.
A Givealittle has been set up to assist the family with "funeral costs, day to day family expenses and supplementing income to free family up to be together during this time".
More than $14,000 has been donated so far. A meal train has also been set up to provide meals for the Halford family.
A number of donors posted messages of condolence on the family's Givealittle page.
"So sorry for your loss. My heart goes out to you all. I loved teaching Declan - will never forget his cheeky smile and laugh. Sending all my love to his family and friends," one said.